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 commanded 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
The numbers below refer to the step numbers on the diagnostic table.
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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.
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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.
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This step verifies that 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.
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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.
-
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.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Do any of the DTCs P1223-1244 fail this ignition? | -- | Go to Step 4 | Go to Step 3 |
3 |
Does the DTC fail this ignition? | -- | Go to Step 4 | Go to Intermittent Conditions |
Are DTC P1223, P1232, P1238, and P1241 all set? | -- | Go to Step 9 | Go to Step 5 | |
Are DTC P1226, P1229, P1235, and P1244 all set? | -- | Go to Step 9 | Go to Step 6 | |
Important: Use the J 35616-94 Connector Adapter of the J 35616 to probe the FICM connector. Is the voltage frequency more than the specified value? | 2.9 Hz | Go to Step 12 | Go to Step 7 | |
7 |
Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 8 |
Does the test lamp illuminate on any of the fuel injector control circuits? | -- | Go to Step 10 | Go to Step 15 | |
Is the voltage more than the specified value on any of the fuel injector control circuits? | 1 V | Go to Step 11 | Go to Step 15 | |
10 | Test the appropriate fuel injector control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 13 |
11 | Test the appropriate fuel injector control circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 14 |
12 | Inspect for poor connections at the harness connector of the FICM. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 14 |
13 | Inspect for poor connections at the harness connector of the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 15 |
14 | Replace the FICM. Refer to Fuel Injector Control Module Replacement . Did you complete the replacement? | -- | Go to Step 16 | -- |
15 | Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 16 | -- |
16 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 17 |
17 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK |
