DTC 41

Code 41 Chart:

Code 41 Wiring Diagram:

CIRCUIT DESCRIPTION:

For timing of spark plug firing, a cam sensor "Hall Effect" switch is used. The cam sensor sends a signal (Sync-Pulse) to the ignition module, when cylinder #1 is 25~ after top dead center on the compression stroke. This signal is used to start the correct coil firing sequence, and to enable sequential fuel injection. The engine will continue to run if the cam signal is lost while running. If the failure is in the cam signal output portion of the C3I module (terminal "J") or the "SFI" cam signal circuit 630 to ECM terminal "A11", the ECM will switch to the simulataneous fuel injection mode as long as the fault is present. In either failure mode a Code 41 will be stored.

Code 41 will set when the following conditions are met:

^ Engine is running.
^ Cam sensor signal not received by the ECM in last 1 second interval.

NOTE: Because of all the possible color code combinations used on electrical wiring diagrams, always refer to ECM CONNECTOR IDENTIFICATION under ELECTRICAL AND ELECTRONIC WIRING DIAGRAMS for correct color code identification of circuit.

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. Checks to see if ECM recognizes a problem and sets Code 41. If the engine cranks but will not start and a Code 41 was displayed, the fault is in the ignition system portion of the Cam Sensor circuit and should be diagnosed using CHART A-3.

2. The voltage to ECM terminal "A11" is supplied by the ignition module. If voltage reading is below 6 volts, the fault is in circuit 630, a poor connection at the C3I module, or a faulty C3I module.


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 a damaged Harrness. Inspect ECM harness connectors for backed out terminal "A11," 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 ECM terminal "A11" 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.