Circuit Description
The engine control module (ECM) replicates the signal received from the crankshaft position (CKP) sensor. This signal is sent to the fuel injection control module (FICM) through the engine speed signal circuit. The FICM uses this replicated signal to generate injection current and control the recharge of the fuel injection high voltage circuits. When cranking, the FICM has full control of the fuel injectors. The only input the FICM uses at this time is the engine speed signal from the ECM. The FICM monitors the signal along with the injection request signals from the ECM after the engine is running. If there is a problem with this signal, a DTC could set.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | DTC P0370 High Resolution Circuit |
| • | DTC P0374 High Resolution System Performance |
Conditions for Running the DTC
The engine is cranking or running.
Conditions for Setting the DTC
| • | The FICM does not receive a crank signal, but does receive injection requests from the ECM. |
| OR |
| • | The FICM receives an invalid crank signal from the ECM. |
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records. |
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. |
Diagnostic Aids
A missing high resolution signal will cause a no-start condition. High resistance in the position sensor low reference circuit may cause this DTC to set. If the condition is intermittent, refer to Intermittent Conditions .
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 - Engine Controls? | -- | Go to Step 2 | |
2 |
Does the scan tool display Last Test Failed? | -- | Go to Step 3 | Go to Diagnostic Aids |
3 |
Important: Use the proper terminal from J 35616 Connector Test Adapter Kit.
Does the voltage measure within the specified range? | 5.5-6.3 V | Go to Step 5 | Go to Step 4 |
4 | Does the voltage measure above the specified range? | 5.5-6.3 V | Go to Step 6 | Go to Step 7 |
5 | Test for a short to reference voltage on the engine speed signal circuit. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 8 |
6 |
Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 10 |
7 |
Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 10 |
8 | Test for a poor connection at the FICM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 9 |
9 | Replace the FICM. Refer to Fuel Injector Control Module Replacement . Did you complete the replacement? | -- | Go to Step 12 | -- |
10 | Test for a poor connection at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 11 |
11 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | -- | Go to Step 12 | -- |
12 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 13 |
13 | Observe the Capture Info with a scan tool. Have any other DTCs not been diagnosed? | -- | System OK | |
