P2048

P2048-(DIESEL EXHAUST FLUID) REDUCTANT INJECTOR CIRCUIT LOW




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

The Diesel Exhaust Fluid (DEF) Injector is mounted to the decomposition tube at the inlet of the Selective Catalytic Reduction (SCR) Catalyst. The DEF Dosing Control Unit sends a Pulse Width Modulated (PWM) signal to DEF Injector to vary the amount of fluid sprayed into the exhaust stream. The DEF Dosing Control Unit will illuminate the MIL lamp via the Powertrain Control Module (PCM) immediately after this diagnostic 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 lamp via the PCM immediately after the diagnostic runs and passes for three consecutive key cycles.

- When Monitored:
With the ignition on and the DEF Injector is commanded on.

- Set Condition:
The DEF Dosing Control Unit that the DEF Injector control circuit voltage 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 for one minute, 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 (K428) DEF INJECTOR SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE




1. Stop actuation of the Diesel Exhaust Fluid Doser Pump Override Test.
2. Turn ignition off.
3. Disconnect the DEF Injector harness connector.
4. Disconnect the DEF Dosing Control Unit C1 harness connector.
5. Measure the resistance of the (K428) DEF Injector Signal circuit between the Diesel Exhaust Fluid Injector harness connector and the DEF Dosing Control Unit C1 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 3

No

- Repair the (K428) DEF Injector Signal circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

3. CHECK THE (K426) DEF INJECTOR RETURN CIRCUIT FOR AN OPEN/HIGH RESISTANCE




1. Measure the resistance of the (K426) DEF Injector Return circuit between the Diesel Exhaust Fluid Injector harness connector and the DEF Dosing Control Unit C1 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 4

No

- Repair the (K426) DEF Injector Return circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

4. CHECK THE (K428) DEF INJECTOR SIGNAL CIRCUIT FOR A SHORT TO GROUND




1. Measure the resistance between ground and the (K428) DEF Injector Signal circuit at the Diesel Exhaust Fluid Injector harness connector.

Is the resistance above 10k Ohms?

Yes

- Go To 5

No

- Repair the (K428) DEF Injector Signal circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

5. CHECK THE (K426) DEF INJECTOR RETURN CIRCUIT FOR A SHORT TO GROUND




1. Measure the resistance between ground and the (K426) DEF Injector Return circuit at the Diesel Exhaust Fluid Injector harness connector.

Is the resistance above 10k Ohms?

Yes

- Go To 6

No

- Repair the (K426) DEF Injector Return circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

6. CHECK THE DEF INJECTOR
1. Measure the resistance across the terminals of the DEF Injector.

NOTE: The resistance through the DEF Injector should be between 11.0 Ohms and 13.0 Ohms.

Does the resistance measure between 11.0 Ohms and 13.0 Ohms?

Yes

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

No

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