P245A

P245A-EGR COOLER BYPASS CONTROL CIRCUIT /OPEN




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:
Voltage detected at status line is between 1.0 volt and 1.7 volts for more than 150 seconds consecutively.





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

1. ACTIVE DTC

NOTE: A faulty EGR Outlet Temperature Sensor can cause this DTC to set. Repair any EGR Outlet Temperature Sensor DTCs before proceeding.

NOTE: If DTC P245C or P245D are present, perform those test procedures before proceeding.

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 OPEN/HIGH RESISTANCE




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 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 3

3. EGR COOLER BYPASS VALVE
1. Remove and clean the EGR Cooler and EGR Outlet Temperature Sensor.
2. Reinstall the EGR Cooler and EGR Outlet Temperature Sensor.
3. Turn the ignition on.
4. With the scan tool, erase DTCs.
5. Start the engine and test drive the vehicle.
6. With the scan tool, read DTCs.

Did the DTC reset?

Yes

- Go To 4

No

- Repair complete.

4. EGR COOLER BYPASS VALVE
1. Replace the EGR Cooler Bypass Valve.
2. Turn the ignition on.
3. With the scan tool, erase DTCs.
4. Start the engine and test drive the vehicle.
5. With the scan tool, read DTCs.

Did the DTC reset?

Yes

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

No

- Repair complete.