What are the probable causes of DTC P1633?

P1235 - Fuel Pump Control Out Of Range Note: For LS6/LS8 and Thunderbird, the FPDM functions are incorporated in the Rear Electronics Module (REM). Also, the REM does not use a FPM circuit. Diagnostic information will be sent through SCP.
P1235 indicates that the FPDM has detected an invalid or missing FP circuit signal from the PCM. The FPDM will send a message to the PCM through the FPM circuit, indicating that this failure has been detected. The PCM will set the DTC when the message is received.

• FP circuit open or shorted
• Electronic Throttle Control (ETC) system concern (check for ETC DTC P2105).
• Damaged FPDM.
• Damaged PCM

• The FPDM sends a 25% duty cycle (250 msec ON, 750 msec OFF) through the FPM circuit to the PCM while the fault is being detected by the FPDM. If the fault is no longer detected, the PDM will return to sending an "all OK" (50% duty cycle) message to the PCM. The PCM will keep P1235 stored in Continuous Memory.
• For LS6/LS8 and Thunderbird, check if Electronic Throttle Control (ETC) DTC P2105 is present. An ETC system concern could cause a P1235, and should be diagnosed first.

KB1 DTC P1233 OR P1234: IS DTC P1233 OR P1234 PRESENT IN KEY ON ENGINE OFF SELF TEST Is DTC P1233 or P1234 present in Key On Engine Off Self-Test?
Yes No A hard fault is present. GO to KB2 . The PCM is now receiving a signal from the FPDM. One possible cause of the DTC P1233 or P1234 is that the IFS switch was tripped, then reset.

If engine is now a no start:

Disregard the DTC P1233 or P1234 at this time. RETURN to Section 3 and CONTINUE as directed. After servicing the no start, to diagnose intermittent causes of the DTC P1233 or P1234, RETURN to GO to KB25 .

If engine will start:

GO to KB25 to diagnose intermittent condition. KB2 DOES THE ENGINE START? Does the engine start?
Yes No GO to KB15 (to check the FPM circuit). VERIFY IFS switch is set (button depressed). If OK, GO to KB3 . KB3 CHECK POWER AND GROUND CIRCUITS TO FPDM

• Disconnect FPDM.
• Key on, engine off.
• Measure voltage between the FPDM PWR pin and ground pin at the FPDM harness connector.

Is voltage greater than 10.5 volts?



Yes No Key off. REPLACE FPDM. GO to KB4 . KB4 CHECK POWER TO FPDM

• Key on, engine off.
• Measure voltage between the FPDM PWR pin at the FPDM harness connector and chassis ground.

Is voltage greater than 10.5 volts?



Yes No REPAIR open ground circuit to FPDM. KEY OFF. No power to FPDM.

For Escort, Mustang:

GO to KB5 .

All Others:

GO to KB8 . KB5 CHECK B+ VOLTAGE TO CCRM PIN 11 (FPDM POWER SUPPLY RELAY)

• Disconnect CCRM.
• Measure B+ circuit voltage at Pin 11 of the CCRM harness connector.

Is voltage greater than 10.5 volts?
Yes No For Mustang:

GO to KB6 .

For Escort:

GO to KB7 . VERIFY integrity of related fuse. If OK, REPAIR open B+ circuit. If fuse is damaged, CHECK B+ and FPDM PWR circuits for short to ground before replacing. KB6 CHECK GROUND CIRCUIT TO CCRM PIN 18

• Measure resistance of ground circuit between CCRM harness connector Pin 18 and chassis ground.

Is resistance less than 5.0 ohms?
Yes No GO to KB7 . SERVICE open ground circuit. KB7 CHECK FOR OPEN FPDM PWR CIRCUIT

• Measure resistance of FPDM PWR circuit between CCRM harness connector (pin 5) and FPDM harness connector.

Is resistance less than 5.0 ohms?
Yes No REPLACE CCRM. The FPDM PWR circuit is open. GO to KB13 to help isolate fault. KB8 CHECK B+ VOLTAGE TO FPDM POWER SUPPLY RELAY

• Disconnect FPDM power supply relay.
• Measure B+ circuit voltage at the FPDM power supply relay harness connector.

Is voltage greater than 10.5 volts?
Yes No GO to KB9 . VERIFY integrity of related fuse. If OK, REPAIR open B+ circuit. If fuse is damaged, CHECK B+ and FPDM PWR circuits for short to ground before replacing. KB9 CHECK FOR GROUND TO FPDM POWER SUPPLY RELAY

• Disconnect scan tool from DLC.
• Measure resistance of ground circuit between FPDM power supply relay harness connector and battery negative post.

Is resistance less than 5.0 ohms?
Yes No GO to KB10 . REPAIR open circuit. KB10 CHECK FOR OPEN FPDM PWR CIRCUIT

• Measure resistance of FPDM PWR circuit between FPDM power supply relay harness connector and FPDM harness connector.

Is resistance less than 5.0 ohms?
Yes No RECONNECT FPDM. GO to KB11 . The FPDM PWR circuit is open. GO to KB13 to help isolate fault. KB11 CHECK VPWR CIRCUIT VOLTAGE (IGN START/RUN for Taurus/Sable) TO FPDM POWER SUPPLY RELAY

• Key on, engine off.
• Measure VPWR circuit voltage (IGN START/RUN for Taurus/Sable) at the FPDM power supply relay harness connector.

Is voltage greater than 10.5 volts?
Yes No REPLACE FPDM power supply relay. REPAIR open VPWR (or IGN START/RUN) circuit. KB13 ISOLATE OPEN IN FPDM PWR CIRCUIT

• Disconnect IFS switch.
• Measure resistance of FPDM PWR circuit between IFS switch harness connector and FPDM power supply relay harness connector (for Escort and Mustang, CCRM harness connector [pin 5]).
• Measure resistance of FPDM PWR circuit between FPDM harness connector and IFS switch harness connector.

Are both resistances less than 5.0 ohms?
Yes No VERIFY that the IFS switch is set (button depressed). If OK, REPLACE IFS switch. REPAIR open in appropriate area of FPDM PWR circuit. KB15 CHECK FOR OPEN FPM CIRCUIT

Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

• Disconnect FPDM.
• Disconnect PCM.
• Measure resistance of FPM circuit between PCM harness connector and the FPDM harness connector.

Is resistance less than 5.0 ohms?
Yes No GO to KB16 . REPAIR open circuit. KB16 CHECK FPM CIRCUIT FOR SHORT TO POWER IN HARNESS

• Key on, engine off.
• Measure voltage between FPM circuit at the PCM harness connector and ground.

Is voltage less than 1.0 volt?
Yes No KEY OFF. GO to KB17 . REPAIR short circuit. KB17 CHECK FPM CIRCUIT FOR SHORT TO GROUND IN HARNESS

• Disconnect scan tool from DLC.
• Measure resistance between FPM circuit at the PCM harness connector and ground.

Is resistance greater than 10,000 ohms?
Yes No GO to KB18 . REPAIR short circuit. KB18 CHECK FOR FPM OUTPUT FROM FPDM

• Reconnect FPDM.
• Key on, engine off.
• Measure dc voltage between FPM circuit at the PCM harness connector and ground.

Is voltage between 0.02 and 1.0 volt dc? (It is OK for the voltage to cycle below this range and then return to within range.)
Yes No REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ). REPLACE FPDM. KB25 CHECK CIRCUITS THAT MAY CAUSE AN INTERMITTENT LOSS OF POWER SUPPLY TO THE FPDM. ALSO CHECK FOR INTERMITTENT OPENS OR SHORTS ON THE FPM CIRCUIT.

Note: Be aware that P1233/1234 could be set if the inertia fuel shutoff (IFS) switch was tripped then reset.


Your best bet , take it to a qualified repair shop.

C1123 Vehicle Speed Circuit Fault Overhead Console Module REFER to Section 413-08 .

P1633 - Keep Alive Power (KAPWR) Voltage Too Low Description: Indicates the KAPWR circuit has experienced a voltage interrupt. Possible Causes:

• Open KAPWR circuit
• Intermittent KAPWR

Diagnostic Aids: Loss of KAPWR to the powertrain control module (PCM) results in immediate malfunction indicator lamp (MIL) illumination and DTC P1633. Application Key On Engine Off Key On Engine Running Continuous Memory All GO to Pinpoint Test QB .
QB: DTCs P0603 or P1633: Keep Alive Power (KAPWR)
Introduction QB: Pinpoint Tests This pinpoint test is intended to diagnose the following:

• battery terminal condition
• KAPWR wire routing
• harness circuit: KAPWR
• powertrain control module (PCM) (12A650)

Powertrain Control Module (PCM) Connector

For PCM connector views or reference values, refer to Section 6 .


Vehicle Connector Pin Circuit Edge,
F-150,
Five Hundred,
Freestyle,
Mark LT,
MKX,
Montego 190 Pin B54 KAPWR Escape/Mariner,
Focus 150 (50-50-50) Pin B45 KAPWR Expedition,
Fusion,
Milan,
MKZ,
Navigator 140 Pin B54 KAPWR All other vehicles 170 Pin B45 KAPWR
Do you know how to test automotive electrical circuit's using a DMM - digital multi- meter ?

P0715 Mitsubishi Input Turbine Speed Sensor Circuit Malfunction
- Input/Turbine Speed Sensor Circuit Malfunction - Wiring problem ! Check for 5 volts on the white an violet wire at the input speed sensor . Check for b+ voltage on the black / with white stripe . The last wire is low reference (ground inside the PCM ) Then check continuity Of same wires from PCM connector B-21, Pins 111 -white with violet stripe ,pin 113 brown . Check for open between PCM an the input speed sensor

P1633 - Keep Alive Power (KAPWR) Voltage Too Low Description: Indicates the KAPWR circuit has experienced a voltage interrupt. Possible Causes:

• Open KAPWR circuit
• Intermittent KAPWR

Diagnostic Aids: Loss of KAPWR to the powertrain control module (PCM) results in immediate malfunction indicator lamp (MIL) illumination and DTC P1633. Application Key On Engine Off Key On Engine Running Continuous Memory All GO to Pinpoint Test QB .

Get's voltage signal from the PCM - engine computer ! PCM connector 175B pin # 32 ,pin # 31 is return signal to PCM . This voltage is probably 5volt reference voltage , not battery voltage !
P1781 - 4x4L Switch Out of Self-Test Range Description: The 4x4L switch is an on/off switch. If the powertrain control module (PCM) does not sense low voltage when the switch is on, the DTC sets. Possible Causes:

• 4x4L harness open or shorted
• Damaged electronic shift module

Diagnostic Aids: Verify the 4x4L switch cycles on/off. Application Key On Engine Off Key On Engine Running Continuous Memory All Refer to the Workshop Manual Section 308-07A, Four-Wheel Drive Systems.

Hello Paige ! It sounds like you have a sick vehicle , lets see if I can help you fix it . Well the code you have has to do with lack of voltage to the ECM -engine control module.
P1633 - Keep Alive Power Voltage Too Low Indicates that the Keep Alive Power (KAPWR) circuit has experienced a power interrupt.

• Open KAPWR circuit
• Damaged PCM
• Intermittent KAPWR Circuit

2000 PCED On Board Diagnostics II SECTION 5: Pinpoint Tests Procedure revision date: 01/31/2001 QB: Diagnostic Trouble Code (DTC) P0603/P1605/P1633 > QB: Introduction QB1 CHECK BATTERY TERMINALS

Note: If KAPWR is interrupted to the PCM (that is, when a breakout box is installed or the battery is disconnected), DTC P0603/P1605 can be generated on the first power-up.

• Inspect the battery cables for loose connections, corrosion.

Are the battery terminal connections in good condition? Yes No KEY OFF. Battery terminals are OK. GO to QB2 . REPAIR battery terminals as necessary. QB2 INSPECT ENGINE COMPARTMENT FOR PROPER WIRE ROUTING

• Inspect Electronic Engine Control (EC) System wiring for proximity to ignition components or wires.

Is wiring too close to ignition components or wires? Yes No REROUTE as necessary. Engine compartment wire routing is OK. GO to QB3 . QB3 CHECK KEEP ALIVE POWER (KAPWR) TO PCM

Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

• Disconnect PCM.
• Measure voltage between KAPWR circuit at the PCM harness connector and ground.
• While observing digital multimeter, grasp the Electronic EC harness and wiggle, shake or bend a small section while working from the PCM to the dash panel.

Does the voltage reading indicate less than 10.5 volts? Yes No ISOLATE and REPAIR open circuit. No open in KAPWR harness circuit detected. GO to QB4 . QB4 CHECK FOR REPEAT OF DTC P0603/P1605/P1633

• Reconnect PCM.
• Start engine and allow it to reach operating temperature.
• Run Key On Engine Off Self-Test.
• Retrieve Continuous Memory DTCs.

Is DTC P0603, P1605 or P1633 present? Yes No REPLACE the PCM. REPAIR other DTCs as necessary. If none, testing is complete. You may want to take this to the repair shop , do you own a volt ohm meter ? Do you know how to use one ?

Put OBD2 P1633 into google for the answer

Only have PO Generic Codes-- the same as you should
find & print out

DTC P1409: MEASURE RESISTANCE ACROSS EGR VACUUM REGULATOR SOLENOID
Diagnostic Trouble Code (DTC) P1409 indicates that Self-Test has detected an electrical fault in the EVR circuit.

Possible causes:

Open EVR circuit.
Open VPWR circuit to EGR Vacuum Regulator solenoid.
EVR circuit shorted to VPWR.
EVR circuit shorted to GND.
Damaged EGR Vacuum Regulator solenoid.
Damaged PCM.
Key off.
Disconnect EGR Vacuum Regulator solenoid.
Measure EGR Vacuum Regulator solenoid resistance.
Is solenoid resistance between 26 and 40 ohms?
Yes No
The EGR Vacuum Regulator solenoid resistance is within specification. GO to HE111 . REPLACE EGR Vacuum Regulator solenoid. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test.

HE111 CHECK VPWR CIRCUIT VOLTAGE AT EGR VACUUM REGULATOR SOLENOID
Key on, engine off.
EGR Vacuum Regulator solenoid disconnected.
Measure voltage between VPWR circuit at the EGR Vacuum Regulator solenoid vehicle harness connector and chassis GND.
Is voltage greater than 10.5 volts?
Yes No
GO to HE112 . SERVICE open in VPWR circuit to EGR Vacuum Regulator solenoid. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test.

HE112 CHECK EVR CIRCUIT RESISTANCE
Key off.
EGR Vacuum Regulator solenoid disconnected.
Disconnect PCM. Inspect for damaged or pushed out pins, corrosion, loose wires. Service as necessary.
Install breakout box and leave PCM disconnected.
Measure resistance between Test Pin 47 (EVR) and EVR circuit at the EGR Vacuum Regulator solenoid vehicle harness connector.
Is resistance less than 5.0 ohms?
Yes No
GO to HE113 . SERVICE open in EVR circuit. RECONNECT all components. RERUN Quick Test.

HE113 CHECK EVR CIRCUIT FOR SHORTS TO POWER OR GROUND
Key off.
EGR Vacuum Regulator solenoid disconnected.
Breakout box installed, leave PCM disconnected.
Measure resistance between Test Pin 47 (EVR) and Test Pins 71 and 97 (VPWR) at the breakout box.
Measure resistance between Test Pin 47 (EVR) and Test Pins 24 and 103 (PWR GND) at the breakout box.
Is each resistance greater than 10,000 ohms?
Yes No
REPLACE damaged PCM. RECONNECT all components. RERUN Quick Test. SERVICE EVR circuit for short to VPWR or PWR GND. RECONNECT all components. RERUN Quick Test.

HE120 CONTINUOUS MEMORY DTC P1409: WIGGLE EGR VACUUM REGULATOR SOLENOID WHILE MONITORING VPWR
Continuous Memory DTC P1409 indicates that Continuous Memory Self-Test has detected an electrical malfunction in the EGR Vacuum Regulator solenoid sometime during vehicle operation.

Note: If DTC P1409 was output in Key On Engine Off (KOEO) or Key On Engine Running (KOER) Self-Test, go to HE110 to diagnose present fault.

Possible causes:

Open EVR circuit.
Open VPWR circuit to EGR Vacuum Regulator solenoid.
EVR circuit shorted to VPWR.
EVR circuit shorted to GND.
Damaged EGR Vacuum Regulator solenoid.
Damaged PCM.
Disconnect PCM. Inspect for damaged or pushed out pins, corrosion, loose wires.
Install breakout box, leave PCM disconnected.
Measure voltage between Test Pin 47 (EVR) and Test Pins 24 (PWR GND) at the breakout box.
Key on.
Voltage must read greater than 10.5 volts. For an indication of a fault, look for this voltage to drop while performing the following:
Lightly tap on the EGR Vacuum Regulator solenoid.
Wiggle the EGR Vacuum Regulator solenoid connector.
Grasp the EGR Vacuum Regulator solenoid vehicle harness connector and wiggle wires between solenoid and PCM.
Is a fault indicated?
Yes No
ISOLATE fault and SERVICE as necessary. RECONNECT all components. RERUN Quick Test. Unable to duplicate or identify fault at this time. GO to Pinpoint Test Step Z1 with the following data: DPFEGR and EGRVR PIDs and list of possible causes.

P1633 - Keep Alive Power Voltage Too Low Indicates that the Keep Alive Power (KAPWR) circuit has experienced a power interrupt.

• Open KAPWR circuit
• Damaged PCM
• Intermittent KAPWR Circuit

QB1 CHECK BATTERY TERMINALS

Note: If KAPWR is interrupted to the PCM (that is, when a breakout box is installed or the battery is disconnected), DTC P0603/P1605 can be generated on the first power-up.

• Inspect the battery cables for loose connections, corrosion.

Are the battery terminal connections in good condition? Yes No KEY OFF. Battery terminals are OK. GO to QB2 . REPAIR battery terminals as necessary. QB2 INSPECT ENGINE COMPARTMENT FOR PROPER WIRE ROUTING

• Inspect Electronic Engine Control (EC) System wiring for proximity to ignition components or wires.

Is wiring too close to ignition components or wires? Yes No REROUTE as necessary. Engine compartment wire routing is OK. GO to QB3 . QB3 CHECK KEEP ALIVE POWER (KAPWR) TO PCM

Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

• Disconnect PCM.
• Measure voltage between KAPWR circuit at the PCM harness connector and ground.
• While observing digital multimeter, grasp the Electronic EC harness and wiggle, shake or bend a small section while working from the PCM to the dash panel.

Does the voltage reading indicate less than 10.5 volts? Yes No ISOLATE and REPAIR open circuit. No open in KAPWR harness circuit detected. GO to QB4 . QB4 CHECK FOR REPEAT OF DTC P0603/P1605/P1633

• Reconnect PCM.
• Start engine and allow it to reach operating temperature.
• Run Key On Engine Off Self-Test.
• Retrieve Continuous Memory DTCs.

Is DTC P0603, P1605 or P1633 present? Yes No REPLACE the PCM. REPAIR other DTCs as necessary. If none, testing is complete.

DTC P1705 - NC2 (Direct Clutch Speed Sensor) Revolution Sensor Circuit malfunction or Direct Clutch Speed Sensor Output is 300 RPM or less with Vehicle at 20 MPH or more & with Park/Neutral Position Switch Off

Most probably you have an electrical fault causing the problem and attached is a diagnostic procedure. It could be 2 separate problems and after rectifying the P1705 only would you know it is single or 2. Repair manual shows right on top of transmission, black sensor with single bolt, 2 wire plug. P/N 89413-08020 list price $113.80

NOTE: DTC P1705 is set when PCM receives 2 gear position signals at the same time.

1. Turn ignition on. If any A/T gear position indicator lights remain illuminated when gear selector is moved from that gear, go to next step. If all A/T gear position indicator lights turn off when gear selector is moved from that gear, system is okay at this time.

2. Disconnect A/T gear position switch connector. If all A/T gear position switch indicators go out, replace A/T gear position switch. If all A/T gear position switch indicators do not go out, go to next step.

3. Reconnect A/T gear position switch connector. Shift through all gear positions except Reverse. Using a DVOM, measure voltage between 16-pin PCM harness connector "D", terminal No. 6 (Green/Red wire on 2.3CL or White wire on Accord and Odyssey) and 25-pin PCM harness connector "B" terminals No. 20 or 22 (Brown/Black wires).

If battery voltage is present, go to next step. If battery voltage is not present, check for a short in Green/Red or White wire between 16-pin PCM harness connector "D" and A/T gear position indicator, or A/T gear position switch. Repair as necessary. If Green/Red or White wire is okay, check for loose PCM harness connectors. Replace PCM with a known-good unit if necessary.

4. Shift through all gear positions except Neutral and Park. Measure voltage between 16-pin PCM harness connector "D", terminal No. 13 (Blue/White wire on Accord or Light Green wire on 2.3CL and Odyssey) and 25-pin PCM harness connector "B" terminals No. 20 or 22 (Brown/Black wires). If battery voltage is present, go to next step. If battery voltage is not present, check for a short in Blue/White or Light Green wire between 16-pin PCM harness connector "D" and A/T gear position indicator, or A/T gear position switch. Repair as necessary. If Blue/White or Light Green wire is okay, check for loose PCM harness connectors. Replace PCM with a known-good unit if necessary.

5. Shift through all gear positions except "D4". Measure voltage between 16-pin PCM harness connector "D", terminal No. 9 (Light Green/Black wire on 2.3CL or Yellow wire on Accord and Odyssey) and 25-pin PCM harness connector "B" terminals No. 20 or 22 (Brown/Black wires). If battery voltage is present, go to next step. If battery voltage is not present, check for a short in Light Green/Black or Yellow wire between 16-pin PCM harness connector "D" and A/T gear position switch. Repair as necessary. If Light Green/Black or Yellow wire is okay, check for loose PCM harness connectors. Replace PCM with a known-good unit if necessary.

6. Shift through all gear positions except "D3". Measure voltage between 16-pin PCM harness connector "D", terminal No. 8 (Green/Blue wire on 2.3CL or Pink wire on Accord and Odyssey) and 25-pin PCM harness connector "B" terminals No. 20 or 22 (Brown/Black wires). If battery voltage is present, go to next step. If battery voltage is not present, check for a short in Green/Blue or Pink wire between 16-pin PCM harness connector "D" and A/T gear position indicator, or A/T gear position switch. Repair as necessary. If Green/Blue or Pink wire is okay, check for loose PCM harness connectors. Replace PCM with a known-good unit if necessary.

7. Shift through all gear positions except "2". Measure voltage between 16-pin PCM harness connector "D", terminal No. 14 (Green/Yellow wire on 2.3CL or Blue wire on Accord and Odyssey) and 25-pin PCM harness connector "B" terminals No. 20 or 22 (Brown/Black wires). If battery voltage is present, go to next step. If battery voltage is not present, check for a short in Green/Yellow or Blue wire between 16-pin PCM harness connector "D" and A/T gear position indicator, or A/T gear position switch. Repair as necessary. If Green/Yellow or Blue wire is okay, check for loose PCM harness connectors. Replace PCM with a known-good unit if necessary.

8. Shift through all gear positions except "1". Measure voltage between 16-pin PCM harness connector "D", terminal No. 15 (Light Green/White wire on 2.3CL or Brown wire on Accord and Odyssey) and 25-pin PCM harness connector "B" terminals No. 20 or 22 (Brown/Black wires). If battery voltage is present, check for loose PCM harness connectors. Replace PCM with a known- good unit if necessary. If battery voltage is not present, check for a short in Light Green/White or Brown wire between 16-pin PCM harness connector "D" and A/T gear position indicator, or A/T gear position switch. Repair as necessary. If Light Green/White or Brown wire is okay, check for loose PCM harness connectors. Replace PCM with a known-good unit if necessary.


Hope helps.