Related Tests, Information and Procedures
Multiple ECM Information Sensor DTCs SetCircuit Description
The Engine Control Module (ECM) monitors various sensors to determine the engine operating conditions.
The ECM controls fuel delivery, spark timing, VVT system operation, and emission control device operation based on the sensor inputs.
The ECM provides a sensor ground to all of the sensors.
The ECM applies 5 volts through a pull-up resistor, and determines the status of the following sensors by monitoring the voltage present between the 5-volt supply and the resistor:
- The engine coolant temperature (ECT) sensor
- The intake air temperature (IAT) sensor
The ECM provides the following sensors with a 5-volt reference and a sensor ground signal:
1
- The throttle position (TP) sensor 1, 2
- The acceleration position (AP) sensor 1
- The Vapor Pressure Sensor
- High fuel pressure sensor
- Low fuel pressure sensor
- The crank position sensor (CKP)
- The CAM position sensor 1, 2 (CMP)
- A/C pressure sensor
2
- The acceleration position (AP) sensor 2, 3
The ECM monitors the separate feedback signals from these sensors in order to determine their operating status.
Diagnostic Aids
IMPORTANT: Be sure to inspect ECM and engine grounds for being secure and clean.
Diagnostic Aids:
A short to voltage in one of the sensor input circuits may cause one or more of the following DTCs to be set:
5 Volt supply A:
P1120, P1220, P1221, P1275, P1125, P1295, P1515, P1516, P0336, P0337, P0341, P0342, P0347, P0453, P1241, P1249
5 Volt supply B:
P1280, P1285, P1125, P1290
IMPORTANT: If a sensor input circuit has been shorted to voltage, ensure that the sensor is not damaged. A damaged sensor will continue to indicate a high or low voltage after the affected circuit has been repaired. If the sensor has been damaged, replace it.
An open in the sensor ground circuit between the ECM and the splice will cause one or more of the following DTCs to be set:
5 Volt supply A:
P1120, P1220, P1221, P1275, P1125, P1295, P1515, P1516, P0336, P0337, P0341, P0342, P0346, P0347, P0453, P1241, P1249
5 Volt supply B:
P1280, P1285, P1125, P1290
A short to ground in the 5-volt reference A or B circuit will cause one or more of the following DTCs to be set:
5 Volt supply A:
P1120, P1220, P1221, P1275, P1125, P1295, P1515, P1516, P0336, P0337, P0341, P0342, P0346, P0347, P0452, P1242, P1247
5 Volt supply B:
P1280, P1285, P1125, P1290
Check for the following conditions:
- Poor connection at ECM. Inspect the harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damage terminals, and a poor terminal-to-wire connection.
- Damaged harness. Inspect the wiring harness for damage. If the harness is not damaged, observe an affected sensor fs displayed value on the Tech 2 with the ignition "ON" and the engine "OFF" while you move the connectors and the wiring harnesses related to the following sensors:
- Vapor Pressure (Fuel Tank Pressure) Sensor
- TPS1/TPS2
- APS1/APS2/APS3
- CKP
- CMP1/CMP2
- High fuel pressure sensor
- Low fuel pressure sensor
- A/C pressure sensor
Step 1:
Steps 2- 7:
Steps 8 - 13:
