2001 Saturn L300 computer error

FASTEDDIE47

MEMBER
2001 SATURN L300
6 CYL
2WD
AUTOMATIC
120,000 MILES

I pulled some codes from my car.
Trouble Code: P1779
Engine Torque Delivered To TCM Signal
Trouble Code: P1791
Throttle Pedal Position Signal Malfunction
Trouble Code: P0118
ECT Sensor Circuit High Input (Low Temperature)
Trouble Code: P0123
TP Sensor Circuit High Input
Trouble Code: P0223
Throttle Position Sensor 2 Circuit High Input

i replaced the ECM thinking that was it but no go, I will be greatful for any help

3 Replies

BRIAN 1

MECHANIC
1,030 POSTS

The engine control module (ECM), transaxle control module (TCM), and the body control module (BCM) communicate with each other over the controller area network (CAN) BUS circuits 2500 and 2501. The CAN BUS is a communications protocol that is used by the TCM to communicate vital engine control inputs from a stand-alone engine controller. The diagnostic checks the information received in CAN to determine whether to pass or fail a code. Before checking the information, the TCM makes sure the CAN messages are being received by checking the BUS failure timer.

Conditions for Setting the DTC
DTC P1779, P1791, P1792 or P1795 will set if the TCM did not receive a needed engine parameter over the CAN BUS from the ECM when:

"� Engine speed is greater than 500 rpm for 5 seconds and not at fuel cutoff.

"� System voltage between 8 and 18 volts.

Diagnostic Aids
"� This code does not indicate a problem with the TCM. It does indicate the ECM is not sending the required information to the TCM.

"� Check for and diagnose any DTCs stored in the ECM related to the ECT, pedal position or TP sensor circuits.

"� Check for any DTCs stored in the EBTCM related to the torque reduction/request circuit.
What made you think it was the ECM? And why did you replace it? Did all these codes appear before or after ECM replacement?I would also check for pin tension at the ECM, and any bent or corroded terminals. Post back and will go to the next step.

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Tuesday, July 21st, 2009 AT 8:31 PM

FASTEDDIE47

MEMBER
2 POSTS

I replaced the ECM after testing as best I could and reading some info I got off the net. I have just a busic scantool and volt meter.

This is the info I got off the net.
Trouble Code: P1779
Engine Torque Delivered To TCM Signal

Possible Causes:

Perform an Onboard Diagnostic System Check of the PCM

The PCM is not sending the required information to the TCM (the problem is not related to the TCM)

Check for any trouble codes related to the CAN data bus

PCM has failed

Trouble Code: P1791
Throttle Pedal Position Signal Malfunction

Possible Causes:

Perform an Onboard Diagnostic System Check of the PCM

Check for any trouble codes related to the CAN data bus

PCM has failed

Trouble Code: P0118
ECT Sensor Circuit High Input (Low Temperature)

Possible Causes:

ECT sensor signal circuit is open between the sensor and PCM

ECT sensor signal circuit is shorted to VREF (5v)

ECT sensor is damaged or it has failed (it may be open)

PCM has failed

TSB 01-06-04-005 contains a repair procedure for this code

Trouble Code: P0123
TP Sensor Circuit High Input

Possible Causes:

TP sensor connector is damaged, open or shorted

TP sensor signal circuit is shorted to VREF (5v)

TP sensor ground circuit is open between the sensor and PCM

TP sensor is damaged or it failed (it may be open)

PCM is damaged or it has failed

Trouble Code: P0223
Throttle Position Sensor 2 Circuit High Input

Possible Causes:

TP2 sensor signal circuit is shorted to VREF

TP2 sensor ground circuit is open

TP2 sensor is damaged or it has failed
.
All but one code came back when I replaced the ECM

Trouble Code: P1271
Accelerator Pedal Position Sensor 1-2 Correlation

Possible Causes:

APP sensor connector is damaged, open or shorted

APP sensor assembly is damaged or it has failed
.
Thank you for your help

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Wednesday, July 22nd, 2009 AT 11:55 AM

BRIAN 1

MECHANIC
1,030 POSTS

Follow this for code p1271, To locate an intermittent problem, use the Scan tool to monitor APP SENSOR 1 and APP SENSOR 2 with the ignition On, engine Off and:

"� Accelerator pedal at normal rest position.

"� Accelerator pedal pressed completely to floor

Voltage should be within 0.1 volts of:

Rest
Accelerator Pedal to Floor

APP SENSOR 1
0.40
3.80

APP SENSOR 2
0.20
1.90

If no other DTCs have been set and the voltage readings are not as indicated above, replace APP sensor assembly.

If both P1271 and P1516 are set, circuit 486 or 1274 may be shorted to voltage.

If DTCs P0102, P0108, P0533 and P1271 are set, there may be a short to voltage on circuit 1164.

If DTCs P0103, P0108, P0113, P0118, P0123, P0223, P0341, P0406 and P1271 are set, there may be an open circuit in the 5-volt reference return circuit 652.

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Wednesday, July 22nd, 2009 AT 5:53 PM