2001 INFINITI QX4 diagram

7 CHECK HO2S1 (FRONT) INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal and front HO2S terminal as follows.
Refer to Wiring Diagram.
MTBL0473
Continuity should exist.
3. Check harness continuity between ECM terminal or FRONT HO2S terminal and ground as follows.
Refer to Wiring Diagram.
MTBL0474
Continuity should not exist.
4. Also check harness for short to power.
OK or NG
OK©GO TO 8.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
8 CHECK HEATED OXYGEN SENSOR 1 HEATER (FRONT)
Check resistance between HO2S1 (front) terminals as follows.
SEF969Y
CAUTION:
Discard any heated oxygen sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a
hard surface such as a concrete floor; use a new one.
OK or NG
OK©GO TO 9.
NG©GO TO 13.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0133, P0153 HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1)/(BANK 2)
(RESPONSE MONITORING)
Diagnostic Procedure (Cont'd)
EC-227

Wiring DiagramNBEC0121RIGHT BANKNBEC0121S01
MEC947C
DTC P0134, P0154 HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1)/(BANK 2)
(HIGH VOLTAGE)
Wiring Diagram
EC-234

LEFT BANKNBEC0121S02
MEC948C
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0134, P0154 HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1)/(BANK 2)
(HIGH VOLTAGE)
Wiring Diagram (Cont'd)
EC-235

3 CHECK HO2S1 (FRONT) INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal and HO2S1 terminal as follows.
Refer to Wiring Diagram.
MTBL0475
Continuity should exist.
3. Check harness continuity between ECM terminal or HO2S1 terminal and ground as follows.
Refer to Wiring Diagram.
MTBL0476
Continuity should not exist.
4. Also check harness for short to power.
OK or NG
OK©GO TO 4.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
4 CHECK HO2S1 (FRONT) CONNECTOR FOR WATER
1. Disconnect heated oxygen sensor 1 (front) harness connector.
2. Check connectors for water.
Water should not exist.
OK or NG
OK (With CONSULT-II)©GO TO 5.
OK (Without CONSULT-
II)©GO TO 6.
NG©Repair or replace harness or connectors.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0134, P0154 HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1)/(BANK 2)
(HIGH VOLTAGE)
Diagnostic Procedure (Cont'd)
EC-237

Wiring DiagramNBEC0128RIGHT BANKNBEC0128S01
MEC949C
DTC P0135, P0155 HEATED OXYGEN SENSOR 1 HEATER (FRONT) (BANK
1)/(BANK 2)
Wiring Diagram
EC-242

LEFT BANKNBEC0128S02
MEC950C
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0135, P0155 HEATED OXYGEN SENSOR 1 HEATER (FRONT) (BANK
1)/(BANK 2)
Wiring Diagram (Cont'd)
EC-243

2 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors M32, F23
IFuse block (J/B) connector M10
I15A fuse
IHarness for open or short between heated oxygen sensor 1 (front) and fuse
©Repair harness or connectors.
3 CHECK HO2S1 (FRONT) OUTPUT CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminal and HO2S1 terminal as follows.
Refer to Wiring Diagram.
MTBL0520
Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 4.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
4 CHECK HEATED OXYGEN SENSOR 1 HEATER (FRONT)
Check resistance between HO2S1 (front) terminals as follows.
SEF969Y
CAUTION:
Discard any heated oxygen sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a
hard surface such as a concrete floor; use a new one.
OK or NG
OK©GO TO 6.
NG©GO TO 5.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0135, P0155 HEATED OXYGEN SENSOR 1 HEATER (FRONT) (BANK
1)/(BANK 2)
Diagnostic Procedure (Cont'd)
EC-245

Wiring Diagram=NBEC0136RIGHT BANKNBEC0136S01
MEC951C
DTC P0137, P0157 HEATED OXYGEN SENSOR 2 (REAR) (BANK 1)/(BANK 2)
(MIN. VOLTAGE MONITORING)
Wiring Diagram
EC-250