DTC P1370 IC 4X Reference Circuit 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 too many 4X reference pulses between CAM pulses. The powertrain control module (PCM) checks to see if there are forty-eight 24X reference pulses between CAM pulses, and if there are, the PCM assumes it is receiving valid CAM pulses. Therefore, if the PCM sees more than eight 4X reference pulses between CAM pulses, it sets DTC P1370, because the 4X reference signal must be faulty.

### Conditions for Running the DTC

• | The engine speed is more than 496 RPM.

• | At least 7 CAM pulses received since key ON.

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

• | 48 24X reference pulses received between CAM pulses.

### Conditions for Setting the DTC

The PCM has received more than 8 4X reference pulses between CAM pulses.

### Action Taken When the DTC Sets

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

• | The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records.

### Conditions for Clearing the MIL/DTC

• | The PCM will turn the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail.

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

• | A History DTC will clear after forty consecutive warm-up cycles with no failures of any emission related diagnostic test.

• | Use a scan tool to clear DTCs.

• | Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in Powertrain Control Module Description .

### Test Description

The number below refers to the step number on the diagnostic table.

1. This step is checking for possible cause of noise (extra 4X pulses) on the fuel control (4X) circuit.

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. Check for possible sources of electromagnetic interference (EMI).
2. Possible causes are:

• | Spark plug wires run along side the ignition control module (ICM).

• | High power transmitters operating in the vicinity, such as mobile radios

• | Various testing equipment

• | A battery charger

3. If possible source is found, remove it.

Was any possible source of EMI found and removed?

--

Go to Step 6

Go to Step 3

3 | Clear DTCs and retest. Does DTC P1370 reset? | -- | Go to Step 4 | Go to Diagnostic Aids

4

1. Check terminal contact at IC module connector C4 terminal C.
2. Check terminal contact at PCM connector C1 terminal 12.
3. Repair terminal contact if needed.

Was terminal contact repaired?

--

Go to Step 6

Go to Step 5

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

6

1. Select the Diagnostic Trouble Code (DTC) option and the Clear DTC Information option using 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 using 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 diagnostic ran and passed?

--

Go to Step 7

Go to Step 2

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