Circuit Description
The enhanced ignition system uses the crankshaft position (CKP) sensor to provide a timing input to the control module. Ignition control (IC) spark timing for each cylinder is based on this input. The control module provides the ignition timing signal to the ignition control module (ICM) to control the ignition coil. Each timing pulse detected by the ICM allows the ICM to energize the ignition coil. A large secondary ignition voltage is induced in the secondary coil winding by the primary coil winding. This high voltage is switched to the correct spark plug by the distributor. If the powertrain control module (PCM) detects an unusually high or low voltage on the ignition signal circuit, DTC P0351 sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0351 Ignition Coil 1 Control Circuit
Conditions for Running the DTC
The engine is cranking.
Conditions for Setting the DTC
The ignition control voltage is not between 0.04-4.9 volts.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the 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. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step determines if the DTC is an intermittent.
-
This step verifies if the IC timing signal from the PCM is available at the ignition control module.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
Does DTC P0351 set? | -- | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections | |
Does the voltage measure within the specified range? | 1-4 V | Go to Step 4 | Go to Step 6 | |
4 |
Does the test lamp illuminate? | -- | Go to Step 5 | Go to Step 11 |
5 |
Does the test lamp illuminate? | -- | Go to Step 10 | Go to Step 14 |
6 |
Does the test lamp illuminate? | -- | Go to Step 12 | Go to Step 7 |
7 | Test for an open in the IC timing control circuit between the PCM and the ICM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 8 |
8 |
Does the voltage measure more than the specified value? | 1 V | Go to Step 13 | Go to Step 9 |
9 | Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections or Connector Repairs . Does you find and correct the condition? | -- | Go to Step 17 | Go to Step 16 |
10 | Test for an intermittent and for a poor connection at the ICM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 15 |
11 | Repair the open in the ground circuit. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 17 | -- |
12 | Repair the short to ground in the IC timing control circuit. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 17 | -- |
13 | Repair the short to voltage in the IC timing control circuit. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 17 | -- |
14 | Repair the open in the ignition 1 voltage circuit. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 17 | -- |
15 | Replace the ICM. Refer to Ignition Control Module Replacement . Did you complete the replacement? | -- | Go to Step 17 | -- |
16 | Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 17 | -- |
17 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 18 |
18 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |
