Engine General Information and Diagnosis: 1A-100
4
ECM voltage check
1) Turn OFF ignition switch.
2) Remove ECM from its bracket with ECM connectors
connected.
3) Check for proper connection of ECM connector at “C37-
53” terminal.
4) If OK, measure voltage between “C37-53” terminal of
ECM connector and engine ground with ignition switch
turned ON.
Is voltage 4 – 6 V?
“WHT” wire is open or
high resistance circuit.
Go to Step 5.
5
Wire harness check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Measure resistance between “C37-53” terminal of ECM
connector and engine ground.
Is resistance infinity?
Substitute a known-
good ECM and recheck.
“WHT” wire is shorted to
ground circuit.
6
Wire harness check
1) Measure voltage between “BLK” wire terminal of electric
throttle body assembly connector and engine ground
with ignition switch turned ON.
Is voltage 4 – 6 V?
Go to Step 9.
Go to Step 7.
7
Wire harness check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Check for proper connection of ECM connector at “C37-
54” and “C37-41” terminals.
3) If OK, measure resistance between “GRN” and “BLK”
wire terminals of electric throttle body assembly
connector.
Is resistance infinity?
Go to Step 8.
“BLK” wire is shorted to
“GRN” wire.
8
Wire harness check
1) Measure resistance between “BLK” wire terminal of
electric throttle body assembly connector and engine
ground with ignition switch turned OFF.
Is resistance infinity?
Substitute a known-
good ECM and recheck.
“BLK” wire is shorted to
ground circuit.
9
Electric throttle body assembly check
1) Check throttle pedal position sensor referring to “Throttle
Position Sensor Performance Check” under “Electric
Throttle Body Assembly On-Vehicle Inspection: in
Section 1C”.
Is output voltage within specified value?
Substitute a known-
good ECM and recheck.
Replace electric throttle
body assembly.
Step
Action
Yes
No
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