Spectrum 3.0L GM - Page 121

121
DTC 168 System Voltage Low/High
Step Action Value(s) Yes No
1
 Perform charging system diagnostics.
Was a fault found?
NOTE: Do not probe wires without proper ser-
vice tool. Permanent harness damage may
result.
Repair as ne-
cessary
Go to step 2
2
 Key OFF, disconnect connector ECU-B.
 Using the proper tools, ground ECU-B pin
D4.
 Measure voltage from ECU-B M2 to M1.
Is voltage within range?
Intermittent
problem. Go
to Preliminary
and Intermit-
tent Checks
Go to Step
(3)
3
 Measure voltage from ECU-B M2 to engine
ground.
Is voltage within range?
Check all
grounds and
repair as ne-
cessary. Go
to Step (7)
Go to Step
(4)
4
 Remove Component Power Relay.
 Measure voltage from pins E8 and D8 to en-
gine ground.
Is voltage within range?
System Vol-
tage
Go to Step
(6)
Go to Step
(5)
6
 Key OFF
 Disconnect ECU-B
 Measure the resistance from: ECU-B pin M2
to Component Power Relay pin C9 and ECU-
B pin D4 to Component Power Relay pin A9
Is the resistance less than 5?
Replace the
power latch
relay. Go to
Step (7).
Repair open
in harness as
necessary.
Refer to Wire
Harness
Repair. Go to
Step (7).