P1350

Codes P1350 & P1361, Ignition Control (IC) Circuit:

Cam/Crank Sensor Circuit:

*** This information has been updated according to Technical service Bulletin #516522, dated May 1995.


CIRCUIT DESCRIPTION
The ignition control module sends a spark reference and a fuel control signal to the PCM when the engine is cranking. At the start of crank, the ignition control module controls ignition timing (module mode). When the PCM recognizes the second fuel control pulse, it applies 5 volts to the bypass CKT 424, commanding the ignition control module to switch timing to PCM control. An open in ignition control CKT 423 will set DTC P1350 at start-up. An open in the Ignition Control (IC) circuit or open or grounded bypass circuit at the time the engine is started will set DTC P1361. The engine may be started but will run on module mode timing.

DTC P135O WILL SET WHEN:
^ CKT 423 opens during engine run mode.

DTC P1361 WILL SET WHEN:
^ Open CKT 423 at the time of engine start-up or grounded CKT 423 while engine is running.

OR

^ PCM not commanding IC mode (open or grounded CKT 424) when the engine is started.

ACTION TAKEN (PCM will default to):
When DTC(s) P1350/P1361 are set, the PCM will illuminate the MIL (Service Engine Soon) and remove the 5 volt bypass signal, causing the engine to run on module mode timing.

TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. Checks to see if PCM recognizes a problem. If it does not set DTC P1350/P1361, it is an intermittent problem which could be due to a loose connection.
2. With the PCM disconnected, the ohmmeter should be reading less than 300 ohms, which is the normal resistance of the IC circuit through the ignition control module. A higher resistance would indicate a fault in CKT 423, a poor ignition module connection, or a faulty ignition control module.
3. If test light was "ON" when connected from 12 volts to PCM harness terminal "RB15", either CKT 424 is shorted to ground or the ignition control module is faulty.
4. Checks to see if ignition control module switches when the bypass circuit is energized by 12 volts through the test light. If the ignition control module switches, the ohmmeter reading should shift to over 6,000 ohms.
5. Disconnecting the ignition control module should make the ohmmeter read as if it were monitoring an open circuit (infinite reading). Otherwise, CKT 423 is shorted to ground.

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 terminals "RB15" or "RB16", improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection. and damaged harness.
^ Intermittent test - Monitor a digital voltmeter connected from affected terminal to ground while moving related connectors and wiring harness. If the failure is induced, the voltage reading will change.
^ Refer to DIAGNOSIS BY SYMPTOM/"DETONATION, SPARK KNOCK" Detonation/Spark Knock/Pings