P124B
DTC P1248, P1249, P124A, P124B, P124C, or P124D
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC P1248
- Injector 1 Positive Voltage Control Circuit Shorted to Control Circuit
DTC P1249
- Injector 2 Positive Voltage Control Circuit Shorted to Control Circuit
DTC P124A
- Injector 3 Positive Voltage Control Circuit Shorted to Control Circuit
DTC P124B
- Injector 4 Positive Voltage Control Circuit Shorted to Control Circuit
DTC P124C
- Injector 5 Positive Voltage Control Circuit Shorted to Control Circuit
DTC P124D
- Injector 6 Positive Voltage Control Circuit Shorted to Control Circuit
Diagnostic Fault Information
Circuit/System Description
The engine control module (ECM) supplies voltage to each fuel injector on the injector high voltage supply circuits. The ECM energizes each fuel injector by grounding the high voltage control circuit of the fuel injector. The ECM monitors the status of the injector high voltage supply circuits and the fuel injector high voltage control circuits. When a fuel injector circuit condition is detected by the ECM, the affected fuel injector(s) is disabled.
Conditions for Running the DTC
* The engine is running.
* The ignition voltage is between 11-18 V.
* The DTCs run continuously when the above conditions are met.
Conditions for Setting the DTC
The ECM detects the injector high voltage supply circuit is shorted to the injector high voltage control circuit for greater than 2 s.
Action Taken When the DTC Sets
DTCs P1248, P1249, P124A, P124B, P124C, and P124D are Type A DTCs.
Conditions for Clearing the DTC
DTCs P1248, P1249, P124A, P124B, P124C, and P124D are Type A DTCs.
Diagnostic Aids
* Performing the fuel injector coil test may help isolate an intermittent condition. Refer to Fuel Injector Solenoid Coil Test Fuel Injector Solenoid Coil Test.
* If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the scan tool Injector Circuit Status parameters. An Injector Circuit Status parameter will change from OK or Not Run to Fault if there is a condition with the circuit or a connection.
Reference Information
Schematic Reference
Engine Controls Schematics [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Connector Views
Description and Operation
Fuel System Description Fuel System Description
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Observe the DTC information with a scan tool. DTC P0685 or P1682 should not set.
• If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.
2. Engine operating, observe the DTC information with a scan tool. DTC P1248, P1249, P124A, P124B, P124C, or P124D should not set.
3. Observe the scan tool Misfire Current Counter parameters. The Misfire Current Counters should not increment.
4. Ignition ON, observe the scan tool Cylinder 1-6 Injector Circuit Status parameters. Verify the Injector Circuit Status parameters display OK.
5. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
1. Ignition OFF, disconnect the appropriate multi-way harness connector X160 or X161, at the rear of the intake manifold.
2. Ignition ON, observe the appropriate scan tool Cylinder 1-6 Injector Circuit Status. The parameter should display Open.
• If not the specified value, test the appropriate high voltage supply circuit, ECM side, for a short to ground or the appropriate high voltage control circuit, ECM side, for a short to voltage. If the circuits test normal, replace the K20 ECM.
3. Ignition ON, connect a test lamp between the appropriate high voltage supply circuit and the high voltage control circuit. The Injector Circuit Status should transition from Open to OK.
• If not the specified value, test for the following conditions in the ECM side of the harness:
* An open/high resistance in the high voltage supply circuit
* An open/high resistance in the high voltage control circuit
* A short to ground in the high voltage control circuit
* A short to voltage in the high voltage supply circuit
• If the circuits test normal, replace the K20 ECM.
Note: Testing for the following steps is performed on the fuel injector side of the multi-way harness connector. It may be necessary to remove the intake manifold to isolate the condition.
4. Ignition OFF, measure the resistance between the appropriate high voltage supply circuit and ground. The DMM should display OL ohm.
• If less than the specified range, test the high voltage supply circuit and the high voltage control circuit for a short to ground. If the circuits/connections test normal, test or replace the appropriate Q17 fuel injector(s).
5. Test for 2-3 ohm between the appropriate high voltage supply circuit and high voltage control circuit.
• If less than the specified range, test for a short between the high voltage supply circuit and high voltage control circuit. If the circuits/connections test normal, test or replace the appropriate Q17 fuel injector(s).
• If greater than the specified range, test the high voltage supply circuit and high voltage control circuit for an open/high resistance. If the circuits/connections test normal, test or replace the appropriate Q17 fuel injector.
Component Testing
* Fuel Injector Solenoid Coil Test Fuel Injector Solenoid Coil Test
* Fuel Injector Balance Test Fuel Injector Balance Test
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Fuel Injection Fuel Rail Assembly Replacement - Bank 1 (LF1, LFW) Fuel Injection Fuel Rail Assembly Replacement - Bank 1 (LF1, LFW)
* Fuel Injection Fuel Rail Assembly Replacement - Bank 2 (LF1, LFW) Fuel Injection Fuel Rail Assembly Replacement - Bank 2 (LF1, LFW)
* Control Module References Control Module References for ECM replacement, setup, and programming