Camshaft Position (CMP) Sensor

1994 PCED OBDI-A

SECTION 18A: Diesel Diagnosis — 7.3L DI Engine

G: Camshaft Position (CMP) Sensor

G: Introduction

G1 CLEAR AND ATTEMPT TO REGENERATE DTC 816, 817 AND 818

Clear continuous memory.
Attempt to start engine.

Does engine start?

Yes	No
GO to G2.	GO to G3.

G2 RERUN KOEO: CHECK FOR DTC 816, 817

Increase rpm to greater than 1500 rpm for 10 seconds. Repeat two times.
Key off.
Rerun KOEO Self-Test.

Is Continuous Memory DTC 816, 817 present?

Yes	No
GO to G3.	DTC 816, 817 is intermittent. GO to G8.

G3 CHECK CMP GROUND

Remove CMP sensor harness connector.
Turn ignition key and all accessories off.

CAUTION: Power in the circuit will affect the resistance reading.

Measure resistance from point A in the connector to ground.

Is there continuity?

Yes	No
GO to G5.	GO to G4.

G4 CHECK CMP GROUND HARNESS CONTINUITY

Install breakout box. Leave the PCM disconnected.
Measure continuity from PCM Pin 65 to point A in the CMP sensor harness.

Is there continuity?

Yes	No
REPLACE PCM.	SERVICE open in harness.

G5 CHECK CMP VREF

Turn ignition key on (sensor harness disconnected).
Measure voltage to ground at point B in the sensor harness.

Is 5 volts ± .5 volt present?

Yes	No
GO to G6.	GO to VREF Pinpoint Test B1.

G6 CHECK CMP SIGNAL

Turn ignition key on (sensor harness disconnected).
Measure voltage to ground at point C in the sensor harness.

Is 12 volts ± 1.5 volt present?

Yes	No
REPLACE CMP sensor.	GO to G7.

G7 CHECK CMP SIGNAL HARNESS CONTINUITY

Install breakout box. Leave the PCM disconnected.
Measure continuity from PCM Pin 49 to point C in the CMP sensor harness.

Is there continuity?

Yes	No
GO to G8.	SERVICE open in harness.

G8 CHECK CMP SIGNAL HARNESS SHORT TO GROUND

Install breakout box. Leave the PCM disconnected.
Measure continuity from PCM Pin 49 to ground.

Is there continuity?

Yes	No
SERVICE short in harness.	REPLACE PCM.