EXPERTEC TSB (93-6-36)

EXPERTEC TSB

TECHNICAL SERVICE BULLETIN

SERVICE MANUAL UPDATE-SEC. 6E - ENHANCED DTC 36 DIAG. CHART

Model(s): 1993 Pontiac Firebird (VIN S - RPO L32)

Bulletin No.: Pontiac 93-6-36

Date: 05/12/1993

SERVICE INFORMATION

This bulletin serves to revise the facing page and chart for Diagnostic Trouble Code (DTC) 36 in Section 6E3 "Driveability and Emissions" in the 1993 Firebird service manual with 3.4L (VIN S) engine.

These replacement pages clarify 24X crankshaft position sensor features and diagnosis.

CIRCUIT DESCRIPTION

The 24X sensor is used to improve spark at engine speed up to approximately 2000 RPM. DTC 36 will set if.

• Engine running.
• The ECM detects that six or more 24X crankshaft position sensor reference pulses have not occurred.
• DTC 36 diagnostic is executed once per ignition cycle.

Test Description: Number(s) below refer to circled number(s) on the diagnostic chart.

1. The 24X signal RPM should be the same as engine speed up to approximately 2000 RPM at which time it stops. This test determines if the ECM is putting out a 24X signal.
2. This test determines if signal voltage is present up to the ECM.
3. This test determines if system voltage is present at the sensor input.
4. By applying system voltage to the 24X crankshaft position sensor pigtail circuit, pigtail and sensor integrity can be determined.
5. This test determines ground path continuity.

DIAGNOSTIC AIDS

An intermittent 24X signal error can be caused by poor connections. Ignition feed, reference low and the signal circuits should all be checked for poor connections.

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