2001 INFINITI QX4 Factory Service Manual

Page 761 of 2395

INFINITI QX4 2001  Factory Service Manual 6 CHECK HO2S1 (FRONT) HARNESS PROTECTOR COLOR
1. Turn ignition switch ªOFFº.
2. Check heated oxygen sensor 1 (front) harness protector.
SEF505Y
3. Disconnect corresponding heated oxygen sensor 1 (fr

Page 762 of 2395

INFINITI QX4 2001  Factory Service Manual 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

Page 763 of 2395

INFINITI QX4 2001  Factory Service Manual 9 CHECK MASS AIR FLOW SENSOR
1. Reconnect harness connectors disconnected.
2. Start engine and warm it up to normal operating temperature.
3. Check voltage between ECM terminal 61 (Mass air flow senso

Page 764 of 2395

INFINITI QX4 2001  Factory Service Manual 11 CHECK HEATED OXYGEN SENSOR 1 (FRONT)
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select ªMANU TRIGº and adjust ªTRIGGER POINTº to 100% in ªDATA MONITORº

Page 765 of 2395

INFINITI QX4 2001  Factory Service Manual 12 CHECK HEATED OXYGEN SENSOR 1 (FRONT)
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Set voltmeter probes between ECM terminal 63 (HO2S1 bank 1 right signal) o

Page 766 of 2395

INFINITI QX4 2001  Factory Service Manual SEF463R
SEF288D
Component DescriptionNBEC0116The heated oxygen sensor 1 (front) is placed into the front tube. It
detects the amount of oxygen in the exhaust gas compared to the
outside air. The heate

Page 767 of 2395

INFINITI QX4 2001  Factory Service Manual TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
62 G/BHeated oxygen sensor
1 (front) (bank 2)[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.0 - Approximately 1.0V (Peri-
od

Page 768 of 2395

INFINITI QX4 2001  Factory Service Manual 5) Restart engine and let it idle for 25 seconds.
6) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-236.
WITH GSTNBEC0120S021) Start engine and warm it up to normal operating temperat