Spectrum 3.0L GM, Parts & Service Manual

Page: 215 / 327

215
DTC 522752 Start Failure Due to Cam Signal Error
Step Action Value(s) Yes No
1

Did you perform the On-board diagnostics
(OBD) system check?
Go to step 2
Perform OBD
System check
2

Check connections at C004, ECU-B pin M1,
M2, L1, and ECU-C pins A4 and F1.
Intermittent
problem. Go
to Preliminary
and Intermit-
tent Checks
Go to Step
(3)
3

Key OFF, disconnect C004 Connector.

Key ON, measure voltage across C004 pins
A and C.
Is voltage between 4.8 and 5.2 volts?
Between 4.8
and 5.2 volts
Go to Step
(4)
Go to Step
(5)
4

Reconnect C004.

Using suitable probe, back probe C004 pins
B and C.

Connect a Multi-meter capable of measuring
Duty Cycle,
+
to pin B,
-
to pin C.

Crank the engine.
Does the duty cycle read 90% (or 10%)? Duty
cycle can show either 90% or 10% ±5% depend-
ing on the meter.
Go to Step
(5)
Replace Cam
Sensor, Go to
Step (9)
5

Wiring check

Key OFF, disconnect ECU-C and C004

Measure resistance from :

C004 pin A to ECU-C pin A4

C004 pin B to ECU-C pin F1

C004 pin C to ECU-B pin M2
Is resistance less than 5
Ω ?
<5 Ω
Go to Step
(6)
Repair the
circuit as ne-
cessary.
Refer to Wire
Harness
Repair. Go to
Step (9)
6

Key OFF, disconnect ECU-C and C004

Measure resistance from :

C004 pin A to ground.

C004 pin B to ground

C004 pin C to ground
Is resistance greater than 30M
Ω ?
>30M Ω
Go to Step
(7)
Repair short
to ground as
necessary.
Refer to Wire
Harness
Repair. Go to
Step (9)
7

Key OFF, disconnect ECU-C and C004

Measure resistance from :

C004 pin A to C004 pin B

C004 pin A to C004 pin C

C004 pin B to C004 pin C
Is resistance greater than 30M Ω ?
>30M Ω
Go to Step
(8)
Repair short
in harness.
Refer to Wire
Harness re-
pair. Go to
Step (9)
8

Replace ECU computer.
Is replacement completed?
Go to Step
(9)