6-1-14
ENGINE DIAGNOSIS (RHZ ENGINE WITH TRIPLE-CONNECTOR ECM)
TROUBLESHOOTING
STEP
ACTION
YES
NO
1
Was “ENGINE DIAG. FLOW TABLE” performed?
Go to Step 2.
Go to “ENGINE DIAG.
FLOW TABLE”.
2
Check IAT Sensor and Its Circuit.
1) Connect scan tool with ignition switch OFF.
2) Turn ignition switch ON.
3) Check intake air temp. displayed on scan tool.
Is – 40
_
C (– 40
_
F) or 131
_
C (268
_
F) indicated?
Go to Step 3.
Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection”
in Section 0A.
3
Check Wire Harness.
1) Disconnect MAF sensor (built-in IAT sensor)
connector with ignition switch OFF.
2) Check for proper connection to MAF sensor
(built-in IAT sensor) at “PPL / RED” and
“BRN / BLU” wire terminals.
3) If OK, then with ignition switch ON, is voltage
applied to “PPL / RED” wire terminal of harness
side about 5 V?
Go to Step 4.
“PPL / RED” wire open
or shorted to power, or
poor E228-28
connection.
If wire and connection
are OK, substitute a
known-good ECM and
recheck.
4
Does scan tool indicate – 40
_
C (– 40
_
F) at Step 2?
Go to Step 6.
Go to Step 5.
5
Check Wire Harness.
1) Disconnect MAF sensor connector.
2) Check intake air temp. displayed on scan tool.
Is – 40
_
C (– 40
_
F) indicated?
Replace MAP
sensor.
“PPL / RED” wire
shorted to ground.
If wire is OK, substitute
a known-good ECM
and recheck.
6
Check Wire Harness.
1) Using service wire, connect MAF sensor (built-in
IAT sensor) connector terminals. (between
“PPL / RED” wire terminal and “BRN / BLU” wire
terminal of harness side)
2) Turn ignition switch ON and check intake air
temp. displayed on scan tool.
Is 131
_
C (268
_
F) indicated?
Replace MAF
sensor (built-in IAT
sensor).
“BRN / BLU” wire open
or poor E228-30
connection.
If wire and connection
are OK, substitute a
known-good ECM
and recheck.
