ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-91
1. Relay box
2. “PTC”
INSPECTION
STEP ACTION YES NO
1 Was “ENGINE DIAG. FLOW TABLE” performed? Go to Step 2. Go to “ENGINE DIAG.
FLOW TABLE”.
2 Check EFE Heater and Its Circuit.
Check for voltage at terminal C01-12 of ECM (PCM)
connector connected, under following each
condition.
During engine warming up (Coolant temp.:
Below 80_C, 176_F, Engine speed: Over 750 r/min):
Over 1.0 V
After warming up: Below 1.0 V
Is each voltage as specified?
Intermittent trouble.
Check for intermittent
referring to
“Intermittent and Poor
Connection” in
Section 0A.
Go to Step 3.
3 Check EFE Heater Relay.
1) Turn OFF ignition switch and remove EFE heater
relay (“PTC”). See Fig. 2.
2) Check for proper connection to relay at terminal
3 and 4. See Fig. 3.
3) Check resistance between each two terminals.
Between terminals 1 and 2: Infinity
Between terminals 3 and 4: 100 – 120 Ω
4) Check that there is continuity between terminals
1 and 2 when battery is connected to terminals
3 and 4. See Fig. 4.
Is EFE heater relay in good condition?
Go to Step 4. Replace EFE heater
relay.
4 Check EFE Heater and Its Circuit.
1) Turn ignition switch OFF and disconnect ECM
(PCM) connectors.
2) Check for proper connection to ECM (PCM) at
terminals C02-25 and C01-12.
3) If OK, then measure resistance between terminal
C01-12 and ground.
Is it 0.5 – 30 Ω at 20_C (68_F)?
“W”, “Y/R” or “W/B”
circuit open or short.
If wire and
connections are OK,
substitute a known-
good ECM (PCM) and
recheck.
“W/B” circuit open or
short.
If wire and
connections are OK,
replace EFE heater.
Fig 1. for Step 4 Fig. 2 for Step 3 Fig. 3 for Step 3
Fig. 4 for Step 3
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