ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-53
TROUBLESHOOTING
Step Action Yes No
1 Was “ENGINE DIAG. FLOW TABLE” per-
formed?
Go to Step 2. Go to “ENGINE DIAG.
FLOW TABLE” in this
section.
2 Check ECT sensor and its circuit :
1) Connect scan tool with ignition switch OFF.
2) Turn ignition switch ON.
3) Check engine coolant temp. displayed on
scan tool.
Is – 40°C (– 40°F) or 164°C (327°F) indicated?
Go to Step 3. Intermittent trouble.
Check for intermittent
referring to “INTERMIT-
TENT AND POOR CON-
NECTION” in Section 0A.
3 Check wire harness :
1) Disconnect ECT sensor connector with igni-
tion switch OFF.
2) Check for proper connection to ECT sensor
at “ORN/BLK” and “GRY/YEL” wire termi-
nals.
If OK, then with ignition switch ON, is voltage
applied to “ORN/BLK” wire terminal about 4 – 6
V?
Go to Step 4. “ORN/BLK” wire open or
short, or poor C51-3-2
connection.
If wire and connection are
OK, substitute a known-
good ECM (PCM) and
recheck.
4 Check wire harness :
1) Using service wire, connect ECT sensor
connector terminals.
2) Turn ignition switch ON and check engine
coolant temp. displayed on scan tool.
Is 164°C (327°F) indicated?
Replace ECT sensor. “GRY/YEL” wire open or
poor C51-3-23 connec-
tion.
If wire and connection are
OK, substitute a known-
good ECM (PCM) and
recheck.
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