P245D

P245D-EGR COOLER BYPASS CONTROL CIRCUIT HIGH




For a complete wiring diagram, refer to the Wiring Information Electrical Diagrams.
Theory of Operation

The Exhaust Gas Recirculation (EGR) Cooler Bypass Valve is used to redirect the EGR gases around the cooler when the engine is in an active regeneration mode. This is to prevent EGR cooler fouling. The EGR Cooler Bypass Valve is a smart device which communicates it's status to the Engine Control Module (ECM). At key on the ECM drives the signal line low and then high and monitors the correct status response from the EGR Cooler Bypass Valve. Throughout engine operation the ECM sends commands to the EGR Cooler Bypass Valve over the signal circuit. EGR Cooler Bypass Valve status line voltage should be within 5-8 volts. When a fault occurs the EGR Cooler Bypass valve will send a signal between 1.0 and 1.7 volts on the status line to the ECM. The ECM also monitors exhaust gas recirculation temperature to determine if the EGR Cooler Bypass Valve was in bypass mode incorrectly. The ECM will light a MIL lamp immediately after this diagnostic runs and fails. The ECM will turn off the MIL lamp after the diagnostic passes in four consecutive drive cycles.

- When Monitored:
Key on

- Set Condition:
EGR Cooler Bypass Valve is commanded on by the Engine Control Module (ECM), and feedback is reading low on signal circuit.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. ACTIVE DTC
1. Turn the ignition on.
2. With the scan tool, record all Freeze frame data.
3. With the scan tool, erase DTCs.
4. Turn the ignition off for 30 seconds.
5. Start the engine.
6. With the scan tool, read DTCs.

Did the DTC reset?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION - 6.7L diagnostic procedure. Intermittent Condition Test.

2. (K670) EGR COOLER BYPASS VALVE SIGNAL CIRCUIT SHORTED TO GROUND




1. Turn the ignition off.
2. Disconnect the EGR Cooler Bypass Valve harness connector.
3. Disconnect the ECM C1 harness connector.
4. Measure the resistance between ground and the (K670) EGR Cooler Bypass Valve Signal circuit at the EGR Cooler Bypass Valve harness connector.

Is the resistance below 10k Ohms?

Yes

- Repair the short to ground in the (K670) EGR Cooler Bypass Valve Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 3

3. ECM




1. Reconnect the ECM C1 harness connector.
2. Turn the ignition on.
3. While monitoring a scan tool, connect a jumper between 12-volts and the (K670) EGR Cooler Bypass Valve Signal circuit.

Did P245C become active?

Yes

- Replace the EGR Cooler Bypass Valve.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Replace and program the Engine Control Module (ECM). Programming and Relearning.