EN(H4DOTC)(diag)-313
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
Check
Yes
No
1
CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed?
Check DTC using
“List of Diagnostic
Trouble Code
(DTC)”. <Ref. to
EN(H4DOTC)(diag)
-81, List of Diag-
nostic Trouble
Code (DTC).>
Go to step 2.
2
CHECK FRONT OXYGEN (A/F) SENSOR
CONNECTOR AND COUPLING CONNEC-
TOR.
Has water entered the connec-
tor?
Completely
remove any water
inside.
Go to step 3.
3
CHECK HARNESS BETWEEN ECM AND
FRONT OXYGEN (A/F) SENSOR CONNEC-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and
front oxygen (A/F) sensor.
3) Measure the resistance of harness between
ECM and front oxygen (A/F) sensor connector.
Connector & terminal
(B135) No. 9 — (E79) No. 1:
(B135) No. 8 — (E79) No. 3:
Is the resistance less than 1
:? Go to step 4.
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM and front oxy-
gen (A/F) sensor
connector
• Poor contact of
coupling connector
4
CHECK HARNESS BETWEEN ECM AND
FRONT OXYGEN (A/F) SENSOR CONNEC-
TOR.
Measure the resistance between ECM and
chassis ground.
Connector & terminal
(B135) No. 9 — Chassis ground:
(B135) No. 8 — Chassis ground:
Is the resistance 1 M
: or
more?
Go to step 5.
Repair the ground
short circuit of har-
ness between
ECM and front oxy-
gen (A/F) sensor
connector.
5
CHECK OUTPUT SIGNAL FOR ECM.
1) Connect the ECM.
2) Turn the ignition switch to ON.
3) Measure the voltage between front oxygen
(A/F) sensor connector and chassis ground.
Connector & terminal
(E79) No. 1 (+) — Chassis ground (–):
Is the voltage 4.5 V or more?
Go to step 7.
Go to step 6.
6
CHECK OUTPUT SIGNAL FOR ECM.
Measure the voltage between front oxygen (A/F)
sensor connector and chassis ground.
Connector & terminal
(E79) No. 3 (+) — Chassis ground (–):
Is the voltage 4.95 V or more?
Go to step 7.
Go to step 8.
7
CHECK OUTPUT SIGNAL FOR ECM.
Measure the voltage between front oxygen (A/F)
sensor connector and chassis ground.
Connector & terminal
(E79) No. 1 (+) — Chassis ground (–):
(E79) No. 3 (+) — Chassis ground (–):
Is the voltage 8 V or more?
Repair the short
circuit to power in
the harness
between ECM and
front oxygen (A/F)
sensor connector.
After repair,
replace the ECM.
<Ref. to
FU(H4DOTC)-52,
Engine Control
Module (ECM).>
Repair the poor
contact of ECM
connector.
8
CHECK EXHAUST SYSTEM.
Are there holes or loose bolts
on exhaust system?
Repair the exhaust
system.
Go to step 9.