ENGINE GENERAL INFORMATION AND DIAGNOSIS (M13 ENGINE) 6-2-83
5 Check wire circuit.
1) Disconnect connectors from ECM with ignition
switch turned OFF.
2) Measure resistance between “WHT/GRN” wire ter-
minal of ECM connector and body ground and
between “GRY” wire terminal of ECM connector and
body ground.
Is resistance infinity?
Go to Step 6. “WHT/GRN” and/or
“GRY” wire shorted
to ground circuit.
If wire are OK, sub-
stitute a known-
good ECM and
recheck.
6 Check wire circuit.
1) Turn ON ignition switch.
2) Check voltage between “WHT/GRN” wire terminal of
ECM connector and body ground and between
“GRY” wire terminal of ECM connector and body
ground.
Is voltage about 0 V at each terminal?
Go to Step 7. “WHT/GRN” and/or
“GRY” wire shorted
to power circuit.
If wire are OK, sub-
stitute a known-
good ECM and
recheck.
7 Check wire circuit.
1) Measure resistance between “E22-34” wire terminal
of ECM connector and “GRY” wire terminal of TP
sensor connector with ignition switch turned OFF.
Is resistance below 5
Ω
?
Go to Step 8. “GRY” wire in high
resistance circuit.
8 Check ground circuit.
1) Connect connectors to ECM.
2) Check for proper connection of MAP sensor connec-
tor at “BRN/WHT” wire terminal.
3) Measure resistance between “BRN/WHT” wire ter-
minal of MAP sensor connector and body ground.
Is resistance below 5
Ω
?
Go to Step 10. Go to Step 9.
9 Check ground circuit.
1) Measure resistance between “E22-28” wire terminal
of ECM connector and body ground.
Is resistance below 5
Ω
?
“BRN/WHT” wire open
circuit or high resistance
circuit.
Poor “E22-28” connec-
tion.
Faulty ECM ground
circuit.
If circuit are OK,
substitute a known-
good ECM and
recheck.
10 Check TP sensor.
1) Turn OFF ignition switch.
2) Disconnect TP sensor connector.
3) Check for proper connection to TP sensor at each
terminal.
4) If OK, then measure resistance between TP sensor
terminals and check if each measured value is as
specified. See Fig. 2.
TP sensor resistance
Between 1 and 3: 4.0 – 6.0 k
Ω
Between 1 and 2: 0.1 – 6.5 k
Ω
, varying according to
throttle valve opening.
Are measured values as specified?
Go to Step 11. Replace TP sensor.
Step Action Yes No
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