P2425-EGR COOLING VALVE CONTROL CIRCUIT OPEN
For a complete wiring diagram Refer to Section 8W
- When Monitored:
With the ignition on and the ECM EGR Cooler Bypass command off.
- Set Condition:
The ECM does not detect voltage on the EGR Cooler Bypass Control circuit.
| Possible Causes |
| INTERMITTENT CONDITION |
| (K344) MAIN RELAY OUTPUT CIRCUITS OPEN |
| (K53) EGR COOLER BYPASS CONTROL CIRCUIT SHORTED TO GROUND |
| (K53) EGR COOLER BYPASS CONTROL CIRCUIT OPEN |
| VALVE BLOCK ASSEMBLY |
| ENGINE CONTROL MODULE |
Diagnostic Test
1. CHECK FOR ACTIVE DTCNOTE: If the ECM detects and stores a DTC, the ECM also stores the engine/vehicle operating conditions under which the DTC was set. Some of these conditions are displayed on the scan tool at the same time the DTC is displayed.
NOTE: Before erasing stored DTCs, record these conditions. Attempting to duplicate these conditions may assist when checking for an active DTC.
Turn the ignition on.
With the scan tool, erase ECM DTCs.
Perform several ignition cycles, turning the ignition off for at least 10 seconds between each ignition cycle.
Monitor the scan tool for ECM DTCs.
Did this DTC set again?
Yes
- Go To 2
No
- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)
2. CHECKING FOR OTHER DTCS
NOTE: An open MAIN Relay power supply to the ECM will cause multiple DTC's including this DTC to set.
NOTE: Check the ECM for other DTC's. If other DTC's are set with this DTC refer to the symptom list and perform the CHECKING THE ECM POWER AND GROUND CIRCUITS test before continuing.
If the ECM power and ground circuits are functioning properly continue with this test.
Yes
- Go To 3
3. (K344) MAIN RELAY OUTPUT CKTS OPEN
Turn the ignition off.
Disconnect the Valve Block Assembly harness connector.
Turn the ignition on.
Using a 12-volt test light connected to ground, check all the (K344) Main Relay Output circuits at the Valve Block Assembly harness connector.
Does the test light illuminate brightly on all circuits?
Yes
- Go To 4
No
- Repair the (K344) Main Relay Output circuit for an open.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
4. (K53) EGR COOLER BYPASS CONTROL CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the ECM harness connectors.
Measure the resistance between ground and the (K53) EGR Cooler Bypass Control circuit at the Valve Block Assembly harness connector.
Is the resistance above 1000 ohms?
Yes
- Go To 5
No
- Repair the (K53) EGR Cooler Bypass Control circuit for a short to ground.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
5. (K53) EGR COOLER BYPASS CONTROL CIRCUIT OPEN
Measure the resistance of the (K53) EGR Cooler Bypass Control circuit between the Valve Block Assembly harness connector and the ECM harness connector.
Is the resistance below 10.0 ohms?
Yes
- Go To 6
No
- Repair the (K53) EGR Cooler Bypass Control circuit for an open.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
6. VALVE BLOCK ASSEMBLY
Install a substitute Valve Block Assembly in place of the vehicle's Valve Block Assembly.
NOTE: Ensure the ECM and Valve Block Assembly harness connectors are connected.
Turn the ignition on.
With the scan tool, check for this DTC to set again.
Did this DTC set again?
Yes
- Replace and program the Engine Control Module in accordance with the Service Information.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
No
- Replace the Valve Block Assembly.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).