DTC P0371 IC 24X Reference CKT Too Many Pulses. Oldsmobile Shelby Series 1 1999

For 1990-2009 cars
Engine Controls Components
Ignition Control Module
OBD II Symbol Description Notice
Powertrain Control Module Connector End Views
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

### Circuit Description

This diagnostic test checks for more than forty-nine 24X reference pulses between CAM pulses. However, the number of 24X pulses is allowed to vary between 47 and 49, as long as any variances toggle between too few pulses and too many pulses. If two variances do not toggle, i.e. they both had 49 reference pulses and eight 4X reference pulses were received between CAM events, then DTC P0371 is set because too many 24X pulses were received.

### Conditions for Running the DTC

• | At least one CAM pulse received in the last 0.25 second.

• | Engine speed is between 496 and 1,200 RPM.

• | Number of CAM pulses since key ON is 7 or more.

• | Eight 4X reference pulses received between CAM pulses.

### Conditions for Setting the DTC

• | More than 49 24X pulses seen between CAM pulses.

| OR

• | The last number of 24X pulses was 49 and the current number of 24X pulses received is 49.

### Action Taken When the DTC Sets

• | The PCM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.

• | The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Freeze Frame and/or Failure Records.

### Conditions for Clearing the MIL/DTC

• | The PCM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.

• | A last test failed, or current DTC, clears when the diagnostic runs and does not fail.

• | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.

• | Use a scan tool in order to clear the MIL and the DTC.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. This step is inspecting for possible sources of electromagnetic interference (EMI) in the circuits associated with the ignition control system. EMI would cause this DTC to set.

2. This step is testing for poor connections at the ignition control module (ICM) that may cause the DTC to set. Inspect all connections at the ICM.

3. This step is testing for poor connections at the PCM that may cause the DTC to set.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check

2

1. Install a scan tool.
2. Idle the engine for 2 minutes.

Does the scan tool indicate that DTC P0371 failed this ignition?

--

Go to Step 3

Go to Diagnostic Aids

3

1. Visually and physically inspect all circuits going to the ICM and the PCM for the following:

• | Routed too close to secondary ignition wires or components

• | Routed too close to after-market add on electrical equipment

• | Routed too close to solenoids, relays, and motors

2. If you find incorrect routing, correct the harness routing.

Did you find and correct the condition?

--

Go to Step 7

Go to Step 4

4

1. Inspect for poor connections at the ICM. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.
2. If you find a poor connection, repair the condition as necessary. Refer to Repairing Connector Terminals in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 7

Go to Step 5

5

1. Inspect for poor connections at the PCM. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.
2. If you find a poor connection, repair the condition as necessary. Refer to Repairing Connector Terminals in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 7

Go to Step 6

6 | Replace the ICM. Refer to Ignition Control Module Replacement . Is the replacement complete? | -- | Go to Step 7 | --

7

1. Select the Diagnostic Trouble Code (DTC) option and the Clear DTC option with the scan tool.
2. Idle the engine at the normal operating temperature.
3. Select the Diagnostic Trouble Code (DTC) option and the Specific DTC option, then enter the DTC number with the scan tool.
4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text, if applicable.

Does the scan tool indicate that this test ran and passed?

--

Go to Step 8

Go to Step 2

8 | Select the Capture Info option and the Review Info option with the scan tool. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to the applicable DTC table | System OK