P208C

P208C-(DIESEL EXHAUST FLUID) REDUCTANT PUMP CONTROL CIRCUIT LOW




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

The Diesel Exhaust Fluid (DEF) Supply Pump Assembly has many functions. It's primary purpose is to draw fluid from the tank and build adequate system pressure for dosing into the exhaust. The DEF Dosing Control Unit provides the 12 Volt supply and ground for the pump. The DEF Dosing Control Unit also provides a Pulse Width Modulated (PWM) signal to the DEF Supply Pump Assembly to control the speed and output of the pump. The DEF Dosing Control Unit will illuminate the MIL light via the Powertrain Control Module (PCM) immediately after the diagnostics runs and fails and diesel exhaust fluid injection into the after treatment system is disabled. The DEF Dosing Control Unit will turn off the MIL light via the PCM when the monitor runs and passes in three consecutive key cycles.

- When Monitored:
Continuously with the ignition on.

- Set Condition:
The DEF Dosing Control Unit detects that the DEF Supply Pump Assembly circuit is below a calibrated value.





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

1. ACTIVE DTC
1. Turn the ignition on, engine not running.
2. With the scan tool, navigate to Systems Tests and actuate the Diesel Exhaust Fluid Doser Pump Override Test.
3. With the scan tool, View DTCs.

Is the DTC Active?

Yes

- Go To 2

No

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

2. CHECK THE (K417) DEF SUPPLY PUMP ASSEMBLY SUPPLY CIRCUIT FOR A SHORT TO GROUND




1. Turn the ignition off.
2. Disconnect the DEF Supply Pump Assembly harness connector.
3. Disconnect the DEF Dosing Control Unit C1 harness connector.
4. Measure the resistance between ground and the (K417) DEF Supply Pump Assembly Supply circuit at the DEF Supply Pump Assembly harness connector.

Is the resistance above 10k Ohms?

Yes

- Go To 3

No

- Repair the (K417) DEF Supply Pump Assembly Supply circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

3. CHECK THE (K418) DEF SUPPLY PUMP ASSEMBLY RETURN CIRCUIT FOR A SHORT TO GROUND




1. Measure the resistance between ground and the (K418) DEF Supply Pump Assembly Return circuit at the DEF Supply Pump Assembly harness connector.

Is the resistance above 10k Ohms?

Yes

- Go To 4

No

- Repair the (K418) DEF Supply Pump Assembly Return circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

4. CHECK THE (K419) DEF SUPPLY PUMP ASSEMBLY SIGNAL CIRCUIT FOR A SHORT TO GROUND




1. Measure the resistance between ground and the (K419) DEF Supply Pump Assembly Signal circuit at the DEF Supply Pump Assembly harness connector.

Is the resistance above 10k Ohms?

Yes

- Go To 5

No

- Repair the (K419) DEF Supply Pump Assembly Signal circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

5. CHECK THE DEF DOSING CONTROL UNIT
1. Reconnect the DEF Dosing Control Unit C1 harness connector.
2. Connect a jumper between the (K417) DEF Supply Pump Assembly Supply circuit and the (K419) DEF Supply Pump Assembly Signal circuit at the DEF Supply Pump Assembly harness connector.

NOTE: Be careful not to spread the terminals.

3. Turn the ignition on.
4. With a scan tool, View DTCs.

Did DTC P208D become active and DTC P208C change to stored?

Yes

- Replace the DEF Supply Pump Assembly. Diesel Exhaust Fluid Pump Assembly - Removal.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Replace the DEF Dosing Control Unit. Diesel Exhaust Fluid Dosing Control Unit - Removal.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.