ENGINE GENERAL INFORMATION AND DIAGNOSIS (M13 ENGINE) 6-2-79
Troubleshooting
Step Action Yes No
1Was “Engine and Emission Control System
Check” performed?
Go to Step 2. Go to “Engine and Emis-
sion Control System
Check” in this section.
2 ECT sensor and its circuit check.
1) Connect scan tool with ignition switch
turned OFF.
2) Turn ignition switch ON.
3) Check engine coolant temp. displayed on
scan tool.
Is –40°C (–40°F) indicated?
Go to Step 3. Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection” in Section 0A.
3 Check ECT voltage.
1) Disconnect connector from ECT sensor with
ignition switch turned OFF.
2) Check for proper connection to ECT sensor
at “YEL/GRN” and “BRN/WHT” wire termi-
nals.
3) If OK, then turn ON ignition switch, check
voltage between “YEL/GRN” wire terminal
of ECT sensor connector and vehicle body
ground. See fig. 1.
Is voltage about 4 – 6 V?
Go to Step 6. Go to Step 4.
4 Check ECM voltage.
1) Disconnect connectors from ECM with igni-
tion switch turned OFF.
2) Remove ECM from vehicle body and con-
nect connectors to ECM.
3) Check for proper connection of ECM con-
nector at “E22-16” terminals.
4) If OK, then turn ON ignition switch, check
voltage between “E22-16” wire terminal of
ECM connector and vehicle body ground.
Is voltage about 4 – 6 V?
“YEL/GRN” wire open cir-
cuit.
If wire and connection are
OK, go to Step 5.
Go to Step 5.
5 Check ECT sensor harness voltage.
1) Disconnect connectors from ECM with igni-
tion switch turned OFF.
2) Turn ON ignition switch.
3) Check voltage between “YEL/GRN” wire
terminal of ECT sensor connector and vehi-
cle body ground.
Is voltage about 0 V?
Go to Step 6. “YEL/GRN” wire shorted
to other circuits.
If wire are OK, substitute
a known-good ECM and
recheck.
6 Check ECT sensor harness resistance.
1) Measure resistance between “E22-16” ter-
minal of ECM connector and “YEL/GRN”
wire terminal of ECT sensor connector with
ignition switch turn OFF.
Is resistance below 5
Ω
?
Go to Step 7. “YEL/GRN” wire in high
resistance circuit.
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