6-2-74 ENGINE GENERAL INFORMATION AND DIAGNOSIS (M13 ENGINE)
2 IAT sensor and its circuit check.
1) Connect scan tool to DLC with ignition
switch turned OFF.
2) Turn ON ignition switch.
3) Check intake air 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 IAT sensor voltage.
1) Disconnect connector from IAT sensor with
ignition switch turned OFF.
2) Check for proper connection to IAT sensor
at “LT GRN” and “BRN/WHT” wire termi-
nals.
3) If OK, then turn ON ignition switch, check
voltage between “LT GRN” wire terminal of
IAT sensor connector and vehicle body
ground. See Fig. 1.
Is voltage about 4 – 6 V?
Go to Step 7. 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 “E22-17” terminal.
4) If OK, then turn ON ignition switch, check
voltage between “E22-17” terminal of ECM
connector and vehicle body ground.
Is voltage about 4 – 6 V?
“LT GRN” wire open cir-
cuit.
If wire and connection are
OK, go to Step 5.
Go to Step 5.
5 Check wire circuit.
1) Disconnect connectors from ECM with igni-
tion switch turned OFF.
2) Turn ON ignition switch.
3) Check voltage between “LT GRN” wire ter-
minal of IAT sensor connector and vehicle
body ground.
Is voltage about 0 V?
Go to Step 6. “LT GRN” wire shorted to
other circuits.
If wire are OK, substitute
a known-good ECM and
recheck.
6 Check wire circuit.
1) Measure resistance between “E22-17” ter-
minal of ECM connector and “LT GRN” wire
terminal of IAT sensor connector with igni-
tion switch turned OFF.
Is resistance below 5
Ω
?
Go to Step 7. “LT GRN” wire in high
resistance circuit.
Step Action Yes No
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