P245C

P245C-EGR COOLER BYPASS CONTROL CIRCUIT LOW




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

The 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 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 off by the Engine Control Module (ECM), and feedback is reading high 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. Turn the ignition on.
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 VOLTAGE
1. Turn the ignition off.
2. Disconnect the EGR Cooler Bypass Valve harness connector.
3. Disconnect the ECM C1 harness connector.
4. Turn the ignition on.
5. Measure the voltage on the (K670) EGR Cooler Bypass Valve Signal circuit at the EGR Cooler Bypass Valve harness connector.

Is there any voltage present?

Yes

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

No

- Go To 3

3. (K670) EGR COOLER BYPASS VALVE SIGNAL CIRCUIT OPEN/HIGH RESISTANCE




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

Is the resistance below 10.0 Ohms?

Yes

- Repair the open or high resistance in the (K670) EGR Cooler Bypass Valve Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 4

4. ENGINE CONTROL MODULE (ECM)




1. Reconnect the ECM C1 harness connector.
2. Reconnect the EGR Cooler Bypass Valve harness connector.
3. Backprobe the (K670) EGR Bypass Signal circuit at the EGR Cooler Bypass Valve harness connector.
4. Connect a jumper between the (K670) EGR Bypass Signal circuit and ground.
5. Turn the ignition on.
6. With the scan tool, read DTCs.

Did P245C go inactive?

Yes

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

No

- Replace Engine Control Module (ECM).
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.