GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 1997 🢒 Aurora 🢒 DTC 🢒 DTC P1377 IC Cam Pulse To 4X Reference Pulse

Refer to

Ignition Control (IC) Module


Object Number: 15990 Size: FS
Fuel Pump/Vehicle Theft Deterrent
MIL/DTC
Engine Controls Components
OBD II Symbol Description Notice
ESD Notice
ESD Notice
 for wiring view .

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 Setting the DTC

Test Conditions

    •  DTC P1376 not set.
    •  Engine speed greater than 496 RPM.
    •  Number of CAM pulses received since key ON is 7 or greater.

Failure Condition

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 (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 PCM Description and Operation.

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° before top dead center), this will be accompanied by severe driveability complaints.

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

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

Step

Action

Value(s)

Yes

No

1

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to A Powertrain On Board Diagnostic (OBD) System Check

2

Are any other DTCs set?

--

Go to DTCs that are set

Go to Step 3

3

Is this DTC set along with a driveability complaint?

--

Go to Step 4

Fault not present. Refer to Diagnostic Aids

4
  1. This DTC will set under any of the following conditions:
    2. • 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 Powertrain Control Module Diagnosis for Verify Repair

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 Powertrain Control Module Diagnosis for Verify Repair

Go to Step 6

6
  1. Check terminal contact at camshaft sensor connector terminals A and B.
  2. Repair terminal contact if needed.

Was terminal contact repaired?

--

Go to Powertrain Control Module Diagnosis for Verify Repair

Go to Step 7

7
  1. Check terminal contact at the ignition control module connector C2 terminals A and B, connector C3 terminal C and connector C4 terminals B and C.
  2. Repair terminal contact if needed.

Was terminal contact repaired?

--

Go to Powertrain Control Module Diagnosis for Verify Repair

Fault not present. Refer to Diagnostic Aids