P0342

DTC P0342 Cam Signal Circuit Diagnostic Chart (Part 1 Of 2):

DTC P0342 Cam Signal Circuit Diagnostic Chart (Part 2 Of 2):

Ignition Control Module Wiring Schematic:

CIRCUIT DESCRIPTION
During cranking, the Ignition Control Module (ICM) monitors the crankshaft position sensor sync signal. The sync signal is used to determine the correct cylinder pair to spark first. After the sync signal has been processed by the ICM, it sends a fuel control reference pulse to the Powertrain Control Module (PCM). When the PCM receives this pulse it will command all six injectors to open for one priming shot of fuel in all cylinders. After the priming, the injectors are left OFF for the next six fuel control reference pulses from the ICM (two crankshaft revolutions). This allows each cylinder a chance to use the fuel from the priming shot. During this waiting period, a cam pulse will have been received by the PCM. Now the PCM begins to operate the injectors sequentially based on true camshaft position. However, if the cam signal is not present at start-up, Diagnostic Trouble Code (DTC) P0342 will set and the PCM will start sequential fuel delivery in random pattern with a 1 in 6 chance that fuel delivery is correct.

DTC PO342 WILL SET WHEN
^ Engine is running.
^ Cam signal not received by PCM for last 5 seconds.

ACTION TAKEN (PCM WILL DEFAULT TO)
With a current DTC P0342 set, the PCM will illuminate the Malfunction Indicator Lamp (MIL) and begin injector sequence based on the last cam pulse. If cam pulses are not present at start-up, the PCM will begin injector sequence based on fuel control pulses received.

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This step verifies proper operation of CKTs 633, 644, and 645.
2. Step verifies the integrity of CKT 630 from ignition control module to PCM.
3. If the camshaft gear magnet is interfacing with the camshaft position sensor the voltage reading will be zero. Bumping engine with the starter should correct the condition.
4. If the voltage reading of "RB9" is constantly varying and connection to the PCM is good, the PCM is faulty.

DIAGNOSTIC AIDS
An intermittent may be caused by a poor connection, rubbed through wire insulation, or a wire broken inside the insulation.

Check for:
^ Poor connection or damaged harness. Inspect PCM harness connectors for backed out terminal "RB9", improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection, and damaged harness.
^ Intermittent test. If connections and harness check OK, monitor a digital voltmeter connected from PCM terminal "RB9" to ground while moving related connectors and wiring harness. If the failure is induced, the voltage reading will change. This may help to isolate the location of the malfunction.