System Operation Description:
The troubleshooting procedures for the diagnostic codes of each pressure sensor are identical. The Engine Control Module (ECM) sends a 5 Volt supply to terminal A of each sensor. The sensor common connection is connected to terminal B of each sensor. The signal voltage from terminal C of each sensor is sent to the appropriate terminal at the J2/P2 ECM connector.
Test Step 1. Check for Active +5 V Sensor Supply Diagnostic Codes
A. Connect the electronic service tool to the data link connector.
B. Turn the key switch to the ON position. Wait at least 15 seconds for activation of the diagnostic codes.
C. Verify if any of the following diagnostic codes are active:
• 232-03 5 Volt Supply voltage high
• 232-04 5 Volt Supply voltage low
Expected Result:
None of the preceding diagnostic codes are active.
Results:
• OK – Proceed to Test Step 2.
• Not OK
Repair: Perform the following diagnostic procedure: Troubleshooting, “5 Volt Engine Pressure Sensor Supply Circuit – Test”.
STOP.
Test Step 2. Inspect Electrical Connectors And Wiring
A. Thoroughly inspect the J2/P2 ECM connector and the connectors for any suspect sensors.
Refer to Troubleshooting, “Electrical Connectors – Inspect” for details.
B. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector and the sensor
connectors that are associated with the active diagnostic code.
Refer to Illustration 89.
C. Check the ECM connector (Allen Head Screw) for the proper torque of 6.0 N·m (55 lb in).
D. Check the harness and wiring for abrasion and pinch points from the sensors back to the ECM.
Expected Result:
All connectors, pins and sockets should be completely coupled and/or inserted and the harness and wiring should be free of corrosion, abrasion or pinch points.
Results:
• OK – Proceed to Test Step 3.
• Not OK
Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.
Verify that the repair eliminates the problem.
Clear all logged diagnostic codes.
STOP.
Test Step 3. Determine the Condition that is Present
A. Turn the key switch to the ON position. Wait at least 15 seconds for activation of the diagnostic codes.
B. Monitor the active diagnostic code screen on the electronic service tool.
C. Determine if the problem is related to a “voltage high” diagnostic code (open circuit) or a “voltage low” diagnostic code (short circuit).
Expected Result:
Either a “voltage low” diagnostic code (short circuit) is active or a “voltage high” diagnostic code (open circuit) is active.
Results:
• Voltage Low (Short) – A “voltage low” diagnostic code (short circuit) is active at this time. Proceed to Test Step 4.
• Voltage High (Open) – A “voltage high” diagnostic code (open circuit) is active at this time. Proceed to Test Step 7.
Test Step 4. Disconnect the Suspect Sensor
A. Turn the key switch to the OFF position.
B. Disconnect the sensor with the “voltage low” diagnostic code (short circuit).
C. Turn the key switch to the ON position. Wait at least 15 seconds for activation of the diagnostic codes.
D. Check for an active “voltage high” diagnostic code (open circuit) for the disconnected sensor.
Expected Result:
A “voltage high” diagnostic code (open circuit) for the disconnected sensor is now active.
Results:
• OK – A “voltage low” diagnostic code (short circuit) was active before disconnecting the sensor. A “voltage high” diagnostic code (open circuit) became active after disconnecting the sensor.
Repair: Temporarily connect a new sensor.
Check for active diagnostic codes.
If the new sensor fixes the problem, reconnect the suspect sensor.
If the problem returns, permanently install the new sensor.
Verify that the repair eliminates the problem.
STOP.
• Not OK – There is a short circuit between the sensor and the ECM.
Repair: Leave the suspect sensor disconnected.
Proceed to Test Step 5.
Test Step 5. Create an Open Circuit at the ECM
A. Turn the key switch to the OFF position.
B. Remove the signal wire of the suspect sensor from the P2 ECM connector.
C. Turn the key switch to the ON position.
D. Check for active diagnostic codes.
Expected Result:
A “voltage high” diagnostic code (open circuit) became active after disconnecting the signal wire.
Results:
• OK – A “voltage low” diagnostic code (short circuit) was active before disconnecting the sensor. A “voltage high” diagnostic code (open circuit) became active after disconnecting the sensor. Proceed to Test Step 6.
• Not OK – There is still a “voltage low” diagnostic code (short circuit).
Repair: Connect a test ECM.
If the test ECM fixes the problem, reconnect the suspect ECM.
If the problem returns, permanently replace the suspect ECM.
Verify that the repair eliminates the problem.
STOP.
Test Step 6. Check the Resistance of the Harness
A. Turn the key switch to the OFF position.
B. Verify that the suspect sensor is disconnected.
C. Measure the resistance between terminal B (Pressure Sensor Common) and terminal C (Signal) of the connector for the suspect sensor on the engine harness.
Expected Result:
The resistance is greater than 20,000 ohms, or “OL” is displayed on the multimeter.
Results:
• OK – The resistance is greater than 20,000 ohms, or “OL” is displayed on the multimeter.
Repair: Check the signal wire for a short to ground.
Repair the faulty wiring or replace the faulty wiring.
Verify that the repair eliminates the problem.
STOP.
• Not OK – There is a short between the pressure sensor common and the signal wire.
Repair: Locate the short between the pressure sensor common and the signal wire.
Repair the faulty wiring or replace the faulty wiring.
Verify that the repair eliminates the problem.
STOP.
Test Step 7. Measure the Sensor Supply Voltage
A. Turn the key switch to the OFF position.
B. Disconnect the suspect sensor.
C. Turn the key switch to the ON position.
D. Measure the voltage from terminal A (Pressure Sensor +5V) to terminal B (Pressure Sensor Common).
Expected Result:
The voltage is 5.0 ± 0.16 VDC.
Results:
• OK – The sensor supply voltage is correct.
Repair: Leave the sensor disconnected.
Proceed to Test Step 8.
• Not OK – The sensor supply voltage is out of the range.
Repair: Check the 5 volt supply wire for an open circuit.
Repair the faulty wiring or replace the faulty wiring.
Verify that the repair eliminates the problem.
STOP.
Test Step 8. Create a Short Circuit at the Sensor
A. Turn the key switch to the ON position.
B. Monitor the active diagnostic code screen.
C. Install a jumper wire between terminal C (Signal) and terminal B (Pressure Sensor Common) of the sensor connector. Wait at least 15 seconds for activation of the “voltage low” diagnostic code (short circuit).
Expected Result:
A “voltage low” diagnostic code (short circuit) is active when the jumper wire is installed. A “voltage high” diagnostic code (open circuit) is active when the jumper wire is removed.
Results:
• OK – The engine harness and the ECM are OK.
Repair: Temporarily connect a new sensor.
If the new sensor fixes the problem, reconnect the suspect sensor.
If the problem returns, permanently replace the suspect sensor.
Verify that the repair eliminates the problem.
STOP.
• Not OK – The “voltage high” diagnostic code (open circuit) remains active when the jumper wire is installed.
Repair: Remove the jumper wire.
Proceed to Test Step 9.
Test Step 9. Create a Short Circuit at the ECM
A. Turn the key switch to the OFF position.
B. Disconnect the J2/P2 ECM connector.
C. Turn the key switch to the ON position.
A “voltage high” diagnostic code (open circuit) should be active for the suspect sensor.
D. Monitor the active diagnostic code screen. Wait at least 15 seconds for activation of the code.
Note: When the P2 ECM connector is disconnected, all of the “voltage high” diagnostic codes (open circuit) for the pressure sensors will be active. This is normal.
E. Install a jumper wire between the terminal for the signal of the suspect sensor and the pressure sensor common on the ECM. Wait at least 15 seconds for activation of the “voltage low” diagnostic code (short circuit).
Expected Result:
A “voltage low” diagnostic code (short circuit) is active for the suspect sensor.
Results:
• OK – The ECM is operating properly.
Repair: Leave the P2 ECM connector disconnected.
Proceed to Test Step 10.
• Not OK – The “voltage high” diagnostic code (open circuit) is still active when the jumper wire is installed.
Repair: Temporarily connect a test ECM.
If the test ECM fixes the problem, reconnect the suspect ECM.
If the problem returns, permanently replace the ECM.
Verify that the repair eliminates the problem.
STOP.
Test Step 10. Check the Resistance of the Harness
A. Turn the key switch to the OFF position.
B. Verify that the suspect sensor is disconnected.
C. Check the resistance between terminal A (Pressure Sensor +5V) and terminal C (Signal) of the connector for the suspect sensor on the engine harness.
Expected Result:
The resistance is greater than 20,000 ohms or “OL” is displayed on the multimeter.
Results:
• OK – There is an open circuit in the signal wire.
Repair: Locate the open in the signal wire.
Repair the faulty wiring or replace the faulty wiring.
Verify that the repair eliminates the problem.
STOP.
• Not OK – There is a short between the 5 volt supply and the signal wire.
Repair: Locate the short between the 5 volt supply and the signal wire.
Repair the faulty wiring or replace the faulty wiring.
Verify that the repair eliminates the problem.
STOP.
