DTC P1377 IC Cam Pulse To 4X Reference Pulse. Oldsmobile Shelby Series 1 1999

For 1990-2009 cars

### Circuit Description

This diagnostic test checks to see if there are eight 4X reference pulses between CAM signals. Do not attempt diagnosis or repair unless the customer is experiencing driveability problems associated with this DTC.

### Conditions for Running the DTC

• | The engine speed is more than 496 RPM.

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

### Conditions for Setting the DTC

The number of 4X reference pulses during two CAM pulses periods is not 16 at least 2 times in a row.

### 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 .

### Diagnostic Aids

Since this DTC can set under normal conditions no diagnosis should be performed unless a driveability complaint is present.

This DTC may also set if all four camshafts are off by one tooth (10 degrees before top dead center). This will be accompanied by severe driveability complaints.

### Test Description

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

1. Other conditions may cause this DTC to set. Diagnose them first.

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 | Are any other DTCs set? | -- | Go to the DTCs that are set | Go to Step 3
3 | Is this DTC set along with a driveability complaint? | -- | Go to Step 4 | Go to Diagnostic Aids

4

1. This DTC will set under any of the following conditions:

• | Too many or too few CAM pulses

• | Too many or too few 4X pulses

2. Check for electromagnetic interference (EMI) being induced in the fuel control(4X) circuit, the CAM signal circuit, the CAM low circuit or the CAM high circuit by improper spark plug routing, or high power transmitters, like mobile radios, operating in the vicinity.

Were any causes of EMI found and repaired?

--

Go to Step 8

Go to Step 5

5 | Check for an intermittent short to ground, short together, or open condition on the fuel control (4X) circuit, the CAM signal circuit, the CAM low circuit, and the CAM high circuit. Were any causes found and repaired? | -- | Go to Step 8 | Go to Step 6

6

1. Check terminal contact at camshaft sensor connector terminals A and B.
2. Repair terminal contact if needed. Refer to Connector Repairs in Wiring Systems.

Was terminal contact repaired?

--

Go to Step 8

Go to Step 7

7

1. Check terminal contact at the ignition control module connector C2 terminals A and C, connector C3 terminals A and B, and connector C4 terminals B and C.
2. Repair terminal contact if needed. Refer to Connector Repairs in Wiring Systems.

Was terminal contact repaired?

--

Go to Step 8

Go to Diagnostic Aids

8

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 9

Go to Step 2

9 | 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