Failure in EEC (PCM) internal voltage - 1990 Ford Escort

DTC P1819
Internal Mode Switch-No Start/Wrong Range

DTC P1825
Internal Mode Switch - Invalid Range

DTC P1826
Internal Mode Switch C Circuit High Voltage

The transmission internal mode switch (IMS) is a sliding contact switch attached to the selector detent inside the transmission side cover. The four inputs to the PCM indicate the position of the transmission range selector. The input voltage level at the PCM is high (B+) when the IMS is open and low when the switch is closed to ground. The four input parameters represented are Signals A, B, C and P (Parity). Refer to Transmission Internal Mode Switch Logic

Install a Scan Tool . A professional scan tool !
Turn ON the ignition, with the engine OFF.
Important: Before clearing the DTC, use the Scan Tool in order to record the Freeze Frame and Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from the PCM.
Record the DTC Freeze Frame and Failure Records.
Clear the DTC.
Select IMS on the Scan Tool .
Place the gear select lever in PARK range, then move to NEUTRAL range.
Does each range selected match the Scan Tool IMS display?
.Replace the lever assembly-manual shaft detent with internal mode switch.
Refer to Transmission Overhaul in the 4T65-E Section of the Transmission Unit Repair Manual.

This trouble code sets when the Powertrain Control Module (PCM) tries to regulate the generator field with no result during monitoring.
The PCM tries to maintain a system voltage between 12.9 volts and 15.0 volts. The voltage determined by the PCM as the final goal for the charging system is called "control" voltage. This control voltage is determined from the battery temperature sensor for ambient sensor and the sensed voltage system voltage at PCM pin #11.
The control voltage is compared to the sensed voltage continuously during running. If the sensed voltage is less than the control voltage, the PCM will supply more ground to the field circuit. If the sensed voltage is more than the control voltage, the PCM will supply less ground to the field circuit.
There are three possible causes for this, the field driver circuit open or shorted, there is an alternator internal open or short os a PCM failure

SYMPTOM
P0123-THROTTLE POSITION SENSOR VOLTAGE HIGH

WHEN MONITORED
With the ignition ON and battery voltage above 10.4 volts .

SET CONDITION
Throttle Position Sensor voltage at the PCM goes above 4.5 volts for 3.2 seconds .

POSSIBLE CAUSES

• Clock spring shorted
• Throttle position sensor sweep
• Intermittent condition
• Throttle position sensor signal circuit shorted to 5 volt supply circuit
• Throttle position sensor signal circuit shorted to battery voltage
• Throttle position sensor internal failure
• Sensor ground circuit open
• Throttle position sensor signal circuit open
• PCM

hope this helps, Tim 423 327 4108

Put OBD2 P1633 into google for the answer

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

P1193 - INLET AIR TEMP SENSOR VOLTAGE HIGH

WHEN MONITORED
With the ignition ON and battery voltage greater than 10.4 volts .

SET CONDITION
The inlet air temperature sensor circuit voltage at the PCM goes above 4.9 volts .

POSSIBLE CAUSES

• Intermittent condition
• IAT sensor signal circuit shorted to battery voltage
• IAT sensor internal failure
• IAT sensor signal circuit open
• Sensor ground circuit open

Hope helps.

this code can sometimes set due to low battery voltage. find the cause of the low battery voltage(this code usually pops up after a car is jump started or the battery is replaced or gone bad). clear the code. if it returns, then yes, the pcm will need replaced.

11 Timing belt skipped 1 tooth or more from initial learned value, Intermittent loss of either camshaft or crankshaft position sensor, No crank reference signal detected during engine cranking
12 Direct battery input to PCM/ECM was disconnected within the last 50 key-on cycles (normal)
13 No change in MAP from start to run
14 MAP sensor voltage too low
15 No vehicle speed sensor signal
17 Closed loop temp not reached or engine cold too long
21 02s sensor problem (oxygen sensor), upstream or down stream
22 Engine coolant temp sensor out of range
23 Intake air temp sensor out of range
24 Throttle Position sensor out of range
25 Idle air control motor circuits, target idle not reached (+/- 200),vacuum leak found
27 Injector control circuit
31 Evap purge flow monitor failure or evap solenoid circuit
32 EGR system failure
33 A/C clutch relay circuit
34 Speed control Solenoid circuits
35 Rad Fan control relay circuit
37 Torque converter clutch solenoid CKT or park/neutral switch failure
41 Generator field not switching properly
42 Fuel pump relay control ckt, Auto shutdown relay control ckt, No ASD relay output voltage at PCM, Fuel level sending unit volts out of range, Fuel level unit No change over miles
43 Multiple/ single cylinder misfire
44 Battery temp sensor volts out of range
46 Charging system voltage too low
51 Fuel system lean
52 Fuel system rich
53 Internal control failure
54 No Cam signal at PCM
55 End of error messages (If you get this only, no errors were found)
62 PCM failure SRI mile not stored
63 PCM Failure EEPROM write denied
64 Catalytic Converter Efficiency Failure
65 Power steering switch failur

EEC is in control

The P01535 refers to the 5 volt reference circuit generated by the PCM. The reference voltage is being pulled low for some reason.
If there are no other codes present, the code is indicating the PCM 5 volt output is too low caused by an internal PCM failure.
If you have a volt meter, check the voltage at the TPS ( gray wire and key in run position ) and see what the actual voltage is.
Let me know and we can go from there.
Regards,

Here is the first half of the codes look till you find the one you have
111 System PASS.
112 ACT sensor circuit grounded.
113 ACT sensor circuit open.
114 ACT sensor is out of Self-Test.
116 ECT sensor is out of Self-Test.
117 ECT sensor circuit grounded.
118 ECT sensor circuit open.
121 TP sensor is out of Self-Test.
122 TP sensor input is less than Self-Test minimum.
123 TP sensor input is greater than Self-Test maximum.
124 TP sensor input voltage is greater than expected.
125 TP sensor input voltage is less than expected.
128 MAP vacuum hose damaged or disconnected.
129 Insufficient MAF input.
136 HEGO sensor circuit indicates system lean (Right HEGO).
137 HEGO sensor circuit indicates system rich (Right HEGO).
139 No HEGO switching (Front Side).
141 Fuel system indicates lean.
144 No HEGO switching (Left Side).
157 MAF sensor circuit open.
158 MAF sensor shorted to power.
159 MAF sensor is out of Self-Test.
167 Insufficient TP input change.
171 Lack of HEGO switching (Rear Side).
172 HEGO sensor circuit indicates lean. (Rear Side).
173 HEGO sensor circuit indicates rich. (Rear Side).
174 Check for diluted engine oil.
175 Lack of HEGO switching (Front Side).
176 HEGO sensor circuit indicates lean. (Front Side).
177 HEGO sensor circuit indicates rich. (Front Side).
178 Check for diluted engine oil.
179 Fuel system at part throttle lean adaptive limit, system rich (Rear Side).
181 Fuel system at part throttle rich adaptive limit, system lean (Rear Side).
182 Fuel system at idle lean adaptive limit, system rich (Rear Side).
183 Fuel system at idle rich adaptive limit, system lean (Rear Side).
184 MAF sensor input voltage is greater than expected, in range.
185 MAF sensor input voltage is less than expected, in range.
186 Closed loop injector pulse width longer than expected.
187 Closed loop injector pulse width shorter than expected.
188 Fuel system at part throttle lean adaptive limit, system rich (Front Side).
189 Fuel system at part throttle rich adaptive limit, system lean (Front Side).
193 Flexible Fuel sensor circuit failure.
211 PIP circuit failure.
212 Loss of tachometer/IDM input.
213 EEC SPOUT circuit open.
214 CID circuit failure.
215 PCM detected coil 1 primary circuit failure.
216 PCM detected coil 2 primary circuit failure.
217 PCM detected coil 3 primary circuit failure.
218 Loss of ignition diagnostic monitor signal-left side.
219 Spark timing defaulted to 10 degrees, spark output circuit open.
221 Spark timing error.
222 Loss of ignition diagnostic monitor signal-right side.
223 Loss of dual plug inhibit control.
224 PCM detected coil 1, 2, 3 or 4 primary circuit failure.
225 Knock not sensed during dynamic response test KOER.
226 Ignition diagnostic monitor signal not received.
232 PCM detected coil 1, 2, 3 or 4 primary circuit failure.
238 PCM detected coil 4 primary circuit failure.
241 Ignition control module to PCM ignition diagnostic monitor pulse width transmission error.
244 Cylinder Identification circuit fault present when cylinder balance test requested.
311 Secondary air injection system inoperative during KOER self-test (bank #1).
312 Secondary air injection system misdirected during KOER self-test.
313 Secondary air injection system not bypassed during KOER self-test.
314 Secondary air injection system inoperative during KOER self-test (bank #2)
326 PFE sensor circuit voltage lower than expected.
327 PFE sensor circuit voltage below Self-Test minimum.
328 Exhaust gas recirculation valve position sensor closed voltage lower than expected.
332 Insufficient EGR flow.
334 Exhaust gas recirculation valve position sensor closed voltage higher than expected.
335 PFE sensor circuit voltage out of Self-Test range.
336 PFE sensor circuit voltage higher than expected.
337 PFE sensor circuit voltage above Self-Test maximum.
338 Engine coolant temperature lower than expected (thermostat test).
339 Engine coolant temperature higher than expected (thermostat test).
341 Octane adjust service pin open.
381 Frequent A/C clutch cycling.
411 Cannot control RPM during KOER low RPM check.
412 Cannot control RPM during KOER high RPM check.
415 Idle Air Control system at maximum adaptive lower limit.
416 Idle Air Control system at upper adaptive learning limit.
452 Insufficient input from VSS.
453 Servo leaking down.
454 Servo leaking.
455 Insufficient RPM increase.
456 Insufficient RPM decrease.
457 Speed control command switch(s) circuit not functioning.
458 Speed control command switch(s) stuck/circuit grounded.
459 Speed control ground circuit open.