P1238

DTC P1238

CIRCUIT DESCRIPTION
The engine control module (ECM) enables the appropriate fuel injector on the compression stroke for each cylinder. The ECM controls the fuel injection control module (FICM) by grounding the control circuit via a solid state device called a driver. The ECM monitors the state of the driver. If the ECM detects an incorrect voltage for the commanded state of an injector driver, DTCs P1223, P1226, P1229, P1232, P1235, P1238, P1241, or P1244 will set.

DTC DESCRIPTORS
This diagnostic procedure supports the following DTCs:
- DTC P1223 Injector 1 Output Circuit
- DTC P1226 Injector 2 Output Circuit
- DTC P1229 Injector 3 Output Circuit
- DTC P1232 Injector 4 Output Circuit
- DTC P1235 Injector 5 Output Circuit
- DTC P1238 Injector 6 Output Circuit
- DTC P1241 Injector 7 Output Circuit
- DTC P1244 Injector 8 Output Circuit

CONDITIONS FOR RUNNING THE DTC
- The engine is running.
- The ignition voltage is between 6-18 volts.

CONDITIONS FOR SETTING THE DTC
- The ECM detects that the command state and the actual state of the control circuit does not match.
- The condition exists for less than 1 second.

ACTION TAKEN WHEN THE DTC SETS
- The control module stores the DTC information into memory when the diagnostic runs and fails.
- The malfunction indicator lamp (MIL) will not illuminate.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
- The driver information center, if equipped, may display a message.

CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

TEST DESCRIPTION

Steps 1-5:

Steps 6-8:

Steps 9-14:

Steps 15-17:

The numbers below refer to the step numbers on the diagnostic table.
4. This step determines if there are 4 fuel injector control circuit DTCs set in a group. A short to voltage will set 4 fuel injector control circuit DTCs for cylinders 1, 4, 6, 7, or cylinders 2, 3, 5, 8. Refer to DTC Descriptors in order to determine which cylinders are affected. If there are more than 4 fuel injector control circuit DTCs set, a short to voltage on a fuel injector control circuit is likely the cause of the concern. A short to voltage will set more than 4 fuel injector control circuit DTCs.
5. This step determines if there are 4 fuel injector control circuit DTCs set in a group. A short to voltage will set 4 fuel injector control circuit DTCs for cylinders 2, 3, 5, 8. If there is only 1 fuel injector DTC set, an open circuit, poor connector, or short to ground is likely the cause of the concern. Refer to DTC Descriptors in order to determine which cylinder is causing the condition.
6. This step verifies the ECM is supplying the appropriate frequency (Hz) through the fuel injector control circuits to the FICM. If the DMM displays 2-4 Hz while cranking, inspect for a poor connection at the FICM.
8. This step is testing for a short to ground on a fuel injector control circuit. If the test lamp illuminates on any fuel injector control circuit, a short to ground is the cause of the condition.
9. This step is testing for a short to a voltage. If the DMM displays a voltage greater than the specified value, a short to voltage is the cause of the condition.