Mechanics

INFINITI I35 SENSOR PROBLEM

2002 Infiniti I35 • 205,999 miles

Lost power and all cel light and dash lights came on. The computer said it was O2 1 and Speed sense. We replaced those parts and drove for 2 days and the same happened again. The computer indicated the same error codes but another mechanic said it was the alternator. Alternator is outputing 13.8 V steady what could it be I need HELP>

Anthony
Avatar
Anthonyfasano
March 5, 2013.



Codes never identify bad parts, just failed systems. What were the codes?

13.8 is too low, it should be 14 to 14.5 volts. Also check for any ac voltage.

Roy

I gave the codes to the Mechanic just found out P1147 but the # 1 issue was O2 # 1 Bank 1 replaced with 13968 Bosch O2 Sensor

the other was Transmission speed sensor P1574 replaced with Dorman 917-611

Alternator voltage is 13.8 -14. Not consistent but new battery 15 days old and connections to sensors secure.

Tiny
Anthonyfasano
Mar 6, 2013.
1147

Component Description
The heated oxygen sensor 2, after three way catalyst, monitors the oxygen level in the exhaust gas on each bank.

Even if switching characteristics of the heated oxygen sensor 1 are shifted, the air fuel ratio is controlled to stoichiometric, by the signal from the heated oxygen sensor 2.

This sensor is made of ceramic zirconia. The zirconia generates voltage from approximately 1 V in richer conditions to 0 V in leaner conditions.

Under normal conditions the heated oxygen sensor 2 is not used for engine control operation.

On Board Diagnosis Logic
The heated oxygen sensor 2 has a much longer switching time between rich and lean than the heated oxygen sensor 1. The oxygen storage capacity before the three way catalyst causes the longer switching time. To judge the malfunctions of heated oxygen sensor 2, ECM monitors whether the maximum voltage of the sensor is sufficiently high during the various driving condition such as fuel-cut.

DTC Confirmation Procedure

NOTE: If "DTC Confirmation Procedure" has been previously conducted, always turn ignition switch "OFF" and wait at least 10 seconds before conducting the next test.

TESTING CONDITION: Open engine hood before conducting following procedure.

WITH CONSULT-II
Start engine and warm it up to normal operating temperature.
Turn ignition switch "OFF" and wait at least 10 seconds.
Turn ignition switch "ON".
Select "DATA MONITOR" mode with CONSULT-II.
Make sure that "COOLAN TEMP/S" indicates more than 70 °C (158 °F).

Select "HO2S2 (B1)/(B2) P1147/P1167" of "HO2S2" in "DTC WORK SUPPORT" mode with CONSULT-II.
Start engine and follow the instruction of CONSULT-II.

Make sure that "OK" is displayed after touching "SELF-DIAG RESULTS". If NG is displayed, refer to "Diagnostic Procedure".

If "CANNOT BE DIAGNOSED" is displayed, perform the following.

Stop engine and cool down until "COOLAN TEMP/S" indicates less than 70 °C (158 °F).
Turn ignition switch "ON".
Select "DATA MONITOR" mode with CONSULT-II.
Start engine.
Return to step 6 again when the "COOLAN TEMP/S" reaches to 70 °C (158 °F).
Overall Function Check
Use this procedure to check the overall function of the heated oxygen sensor 2 circuit. During this check, a DTC might not be confirmed.

WITH GST
Start engine and drive vehicle at a speed of more than 70 km/h (43 MPH) for 2 consecutive minutes.
Stop vehicle with engine running.

Set voltmeter probes between ECM terminal 88 (HO2S2 bank 1 signal) or 90 (HO2S2 bank 2 signal) and engine ground.
Check the voltage when racing up to 4,000 rpm under no load at least 10 times. (Depress and release accelerator pedal as soon as possible.)
The voltage should be above 0.63 V at least once during this procedure.
If the voltage can be confirmed in step 4, step 5 is not necessary.

Keep vehicle at idling for 10 minutes, then check the voltage. Or check the voltage when coasting from 80 km/h (50 MPH) in "D" position with "OD" OFF. The voltage should be above 0.63 V at least once during this procedure.
If NG, go to "Diagnostic Procedure".

Remember, codes never idnetify bad parts, just failed systems

1574
P1574 ASCD Vehicle Speed Sensor

Component Description

NOTE: If DTC P1574 is displayed with DTC U1000, U1001, first perform the trouble diagnosis for DTC U1000, U1001.
See: U Code Charts\U1000\Engine Control System
See: U Code Charts\U1001

If DTC P1574 is displayed with DTC P0500, first perform the trouble diagnosis for DTC P0500. See: P0500

If DTC P1574 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. See: P0605

ECM receives vehicle speed signals via two different lines, and detects vehicle speed for ASCD control.

Vehicle speed signals are input from combination meter and TCM separately.

Signal from TCM is sent via CAN communication line.

Refer to ASCD functions.

On Board Diagnosis Procedure

DTC Confirmation Procedure

CAUTION: Always drive vehicle at a safe speed.

NOTE: If "DTC Confirmation Procedure" has been previously conducted, always turn ignition switch "OFF" and wait at least 10 seconds before conducting the next test.

TESTING CONDITION: STEP 3 may be conducted with the drive wheels lifted in the shop or by driving the vehicle. If a road test is expected to be easier, it is unnecessary to lift the vehicle.

With CONSULT-II
Start engine (TCS switch "OFF").

Lots of things it could be. Doubt it is the speed sensor.

This is why you pay for a real diag from a shop. They will pinpoint the failure without throwing parts at it and not succeeding

Roy

Thank you very detailed. I will show to my shade tree tomorrow.

Tiny
Anthonyfasano
Mar 6, 2013.
Lets hope he understands

Roy