P1350

DTC P1350

Circuit Description

The ignition control module (ICM) controls spark timing when the engine is cranking. During this Bypass mode of operation, the ICM triggers each ignition coil in the proper sequence at a pre-calibrated timing advance. The ICM is connected directly to the powertrain control module (PCM) and includes the following circuits:

* The medium resolution engine speed signal
* The camshaft position signal circuit
* A low reference circuit
* The low resolution engine speed signal circuit
* The ignition control (IC) timing control circuit
* The IC timing signal circuit

When the PCM begins receiving the 3X reference pulses from the ICM and the engine starts, the PCM applies 5 volts to the IC timing signal circuit. This allows the ICM to switch to the IC mode of operation and spark advance to be controlled by the PCM. The PCM monitors the IC timing signal circuit for errors. If the PCM detects a fault, DTC P1350 sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P1350 Ignition Bypass Circuit

Conditions for Running the DTC

* The engine is running or cranking.
* DTC P1350 runs continuously when the above condition is met.

Conditions for Setting the DTC

The PCM detects a fault in the IC timing signal circuit for more than 9 seconds.

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

Step 1 - Step 12:

Step 13 - Step 16:

The number below refers to the step number on the diagnostic table.
3. When the test lamp is tapped on the low resolution engine speed signal circuit, the PCM detects engine speed and applies 5 volts to the IC timing signal circuit.