ENGINE DIAGNOSIS (RHZ ENGINE WITH TRIPLE-CONNECTOR ECM) 6-1-7
1. ECM (PCM)
2. To ignition switch
3. Main fuse
4. Double relay
5. To radiator fan relay No.3
TABLE A-1 MALFUNCTION INDICATOR LAMP CIRCUIT CHECK – MIL DOES NOT COME
“ON” OR DIMS AT IGNITION SWITCH ON (BUT ENGINE AT STOP)
WIRING DIAGRAM
CIRCUIT DESCRIPTION
When the ignition switch is turned ON, ECM causes the main relay to turn ON (close the contact point). Then, ECM
being supplied with the main power, turns ON the malfunction indicator lamp (MIL). When the engine starts to run
and no malfunction is detected in the system, MIL goes OFF but if a malfunction was or is detected, MIL remains
ON even when the engine is running.
INSPECTION
STEP ACTION YES NO
1 MIL Power Supply Check:
1) Turn ignition switch ON.
Do other indicator/warning lights in
combination meter comes ON?
Go to Step 2. “IG” fuse blown, main fuse
blown, Ignition switch
malfunction, “BLK /WHT” circuit
between “IG” fuse and
combination meter or poor
coupler connection at
combination meter.
2 ECM Power and Ground Circuit Check:
Does engine start?
Go to Step 3. Go to TABLE A-3 ECM (PCM)
POWER AND GROUND
CIRCUIT CHECK.
If engine is not cranked, go to
DIAGNOSIS in Section 6G or
6G1.
3 MIL Circuit Check:
1) Turn ignition switch OFF and disconnect
connectors from ECM.
2) Check for proper connection to ECM at
terminal E227-30.
3) If OK, then using service wire, ground
terminal E227-30 in connector disconnected.
Does MIL turn on at ignition switch ON?
Substitute a known-
good ECM (PCM)
and recheck.
Bulb burned out or “PPL/YEL”
wire circuit open.
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