2003 cts codes

Do you know anything about ECM five volt reference circuit's ?
DTC P0641: 5-Volt Reference 1 Circuit
The engine control module (ECM) has 3 internal 5-volt reference busses called 5-volt reference 1, 5-volt reference 2, and 5-volt reference 3. Each reference bus provides 5-volt reference circuits for more than one sensor. Therefore, a fault condition on one 5-volt reference circuit will affect the other 5-volt reference circuits connected to that reference bus. The ECM monitors the voltage on the 5-volt reference busses.

The 5-volt reference 1 bus provides 5 volts to the following sensors:
• The manifold absolute pressure (MAP) sensor
• The clutch apply sensor
• The fuel rail sensor
• The fuel tank pressure (FTP) sensor
• The intake air pressure and temperature sensor

You have a shorted sensor more then likely or wiring problem . Suggest you watch this video .
How to check the 5v reference circuit for short to ground Cadillac

DTC P0532: Air Conditioning A/C Refrigerant Pressure Sensor Circuit Low Voltage
The sensor gets 5 volt ref. voltage from the ECM - engine control module . Three wire sensor , all wires are to an from the ECM .

Circuit/System Description
The engine control module (ECM) monitors the high side refrigerant pressure through the A/C refrigerant pressure sensor. The ECM supplies a 5-volt reference and a low reference to the sensor. Changes in the A/C refrigerant pressure cause the A/C refrigerant pressure sensor signal to the ECM to vary. When the pressure is low, the signal voltage is low. When the pressure is high, the ECM commands the cooling fans on. When pressure is too high or too low, the ECM will not allow the A/C compressor clutch to engage.

Circuit/System Testing
Ignition OFF, disconnect the harness connector at the A/C refrigerant pressure sensor.
Ignition OFF, test for less than 10 ohms between the low reference circuit terminal 1 and ground.
? If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 2 and ground.
? If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
? If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
Verify the scan tool A/C High Side Pressure Sensor parameter is less than 0.1 volts (1 psi).
? If greater than the specified range, test the signal circuit terminal 3 for a short to voltage. If the circuit tests normal, replace the ECM.
Install a 3A fused jumper wire between the signal circuit terminal 3 and the 5-volt reference circuit terminal 2. Verify the scan tool A/C Refrigerant High Side Pressure Sensor parameter is greater than 4.90 volts (425 psi).
? If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
If all circuits test normal, test or replace the A/C refrigerant pressure sensor.

A/C Refrigerant Pressure Sensor
In the engine compartment, on the high pressure refrigerant line

Do you know difference between high an low side lines ?
between alternator an the compressor

If the sensors were replaced an DTC'S come back has to be a wiring problem or PCM ,
The ECM detects that the HO2S heater low control circuit voltage is between 2.6-4.6 volts when the heater is commanded OFF, indicating an open HO2S heater circuit.
Is the fuse open?
All four codes refer to the heating element circuit ! there is a relay in the under hood fuse box that supplies B+ voltage to the O2 sensor heating elements . I would change that or test the relay , videos on you tube on testing relays .
MAIN Relay
--
LO SPEED Relay, HI SPEED Relay, S/P FAN Relay, PRE O2 Fuse, IGN-1 Fuse, ECM Fuse, POST O2 Fuse, and INJ Fuse
Also check
POST O2 Fuse
10 A
HO2S Bank 1 Sensor 2 and HO2S Bank 2 Sensor 2
PRE O2 Fuse
10 A
Heated Oxygen Sensor (HO2S) Bank 1 Sensor 1 and HO2S Bank 2 Sensor 1

The same thing happened to my 03 CTS. The camshaft position sensor code is often thrown for a variety of reasons. In my case somehow the ECM went when the timing belt jumped (after the serpentine belt broke). It was a bear to diagnose but after installing a rebuilt ECM it runs great. (Don't make the mistake I made: the cylinder head gaskets will fit nicely on either side but if not placed on the correct sides you'll block the single oil port which provides engine oil to the head)

Possible causes
- Faulty Engine Control Module (ECM)
- ECM harness is open or shorted
- ECM circuit poor electrical connection
- Shorted sensor on 5 volt circuit
What does this mean? When is the code detected?
The Engine Control Module (ECM) has detected the sensor 5 volt reference circuit voltage is higher or lower than expected
Possible symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
P0641 Chevrolet Description
The control module has 2 internal 5-volt reference buses called "5-volt reference 1" and"5-volt reference 2". Each reference bus provided 5-volt reference circuit for more than one sensor. Therefore, a fault condition on one 5-volt reference circuit will affect the other 5-volt reference circuits connected to the reference bus. The control module monitors the voltage on the 5-volt reference buses.

Read more: http://engine-codes.com/p0641_chevrolet.html#ixzz31AP60YfR

P0234 Description
The boost pressure sensor responds to pressure changes in the intake manifold. This pressure is created by the turbocharger and changes with accelerator pedal position (APP) and engine speed. The engine control module (ECM) uses this information to assist in diagnosis of the barometric pressure (BARO) sensor and to provide engine overboost protection. The boost pressure sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. The engine control module (ECM) supplies 5 volts to the boost pressure sensor on the 5-volt reference 2 circuit, and provides a ground on a low reference circuit. The boost pressure sensor provides a signal to the ECM on a signal circuit relative to the pressure changes. The ECM monitors the boost pressure sensor signal for voltage outside of the normal range. The ECM calculates a predicted value for the boost pressure sensor. The ECM then compares the predicted value to the actual signal.


Read more: http://engine-codes.com/p0234.html#ixzz2e2DssWbP

P0652 DODGE - 5 Volt Sensor Reference 2 Circuit Low
These 5-volt reference circuits are independent of each other outside the PCM, but are bussed together inside the Engine Control Module (ECM). Therefore a circuit condition on one sensor 5-volt reference circuit may affect the other sensor 5-volt reference circuits. The ECM monitors the voltage on the 5-volt reference circuit.

Possible causes
- Shorted sensor
- Shorted sensor circuit
- Failed ECM

When is the code detected? The ECM has detected an out of voltage range on the 5 volt reference circuit 2.

Hope helps.

Hello www_ropesmor,

This code P0123 is Throttle position sensor circuit high input.

There four basic reasons for this code.

1. An open or short to ground between the TPS (throttle position sensor) and the ECM (Engine control module).
2. A short to battery voltage between TPS and the ECM.
3. A short between the TPS wires.
4. A faulty TPS.

See below for connector diagrams.

First, with scan tool monitor TPS with throttle closed voltage should be
I f you don't have a scan tool, back probe terminal 1with a volt meter to ground and you will see the voltage as outlined above otherwise follow the steps below.


1.Check to see if there is about 5 volts at the TPS; with engine off key on disconnect the TPS back probe the harness side terminal 3 to ground with a volt meter if there is about 5 volts go to step 2 if about 5 volts if not repair the 5 volt circuit.

2. Probe the harness side terminal 2 to chassis ground with a volt meter, if voltage above .02 repair circuit 2 short to voltage. If voltage is .02 volts or below go to step 3.

3. Probe the harness side terminal 1 to ground with volt meter if below .5 volts go to step 4 if not repair short to battery between TSP harness and ECM connector

4 Turn the ignition off and disconnect the ECM connector . With an ohm meter measure the resistance between the ECM (terminal C18) and TPS ground circuit it should be below 1 ohm. Measure the resistance between the ECM (terminal C8) and TPS signal circuit it should be below 1 ohm. If not repair the open circuit.

After faulty circuit is found and repaired clear code and verify repair.







I hope this helps.

Regards,

netvan

all your sensors run off the 5 volt ref. so you will have to trace your wiring harness from the pcm\ecm all the way out under the hood to locate the broken or pinched wire.

thats correct, may have bad ecm (computer) or bad wire to crank sensor from ecm, also ive run into this problem and it was the new sensor i put in was no good and aftermarket,also cam sensor can do this, and also make sure the 5 volt feed wire is good,good luck hope this helps.