I have a 2001 Nissan Frontier SE/XE w/ 3.3L 6Cyl engine, no supercharger, 4×4 automatic transmission. I have 4 codes on it right now, which are:
Haynes Repair Manual's description is: Catalyst system fault (left bank).
Mechanics diagnostics description is: Bank 2 Oxygen sensor behind catalytic converter.
Haynes Repair Manual's description is: Idle Air Control Valve or circuit fault.
Also the same codes pending:
I took my truck into the shop to fix the rough idle which I believe was causing the P0505 code and his pending twin. Apparently the little metal arm from the Fast Idle Cam and Thermo Element that makes contact with the Throttle Lever (to maintain proper idle during cold operation) was bent out of position. Most like bent during the removal of the Intake Manifold when I had to replace the Knock Sensor.
After a half completed diagnostic test and a $157 charge to bend the metal arm back into place, the mechanic reset the codes. The truck idled and ran like before. I didn't notice if the Service Engine Light was on before I got home but it was on when I parked the truck.
These codes are, for lack of better words, stuck on my On-Board Diagnosis system. I have an OBD-II code reader which allows me to erase codes as well. Which I have done multiple times, but these stubborn codes don't seem to erase. The tester instantly checks for codes after erasing previous codes. As soon as I erase the codes I keep watching the tester (I do not turn the key to the off position or anything of the sort) and the codes are still there.
I drove 120 miles to try and do a drive cycle or two, hoping that the computer will reanalyze the sensors and relays. Didn't work.
I had a dead battery and replaced it but still the codes are there.
Any way that I know on how to erase a code, I have tried, but they never go away. The computer doesn't even do its system check then turn the Service Engine Light on for these codes.
I don't want to pay another mechanic to do another Dyno on my truck just for them to do basically nothing like the last mechanic.
Is there something I am missing?
Is there something wrong with the Powertrain Control Module?
DTC Confirmation Test (Overall Function Check)
Malfunction is detected when 3-way catalyst does not operate properly. Possible causes are: Defective 3-way catalyst.
Exhaust system damaged or leaking.
Intake air leak.
Defective spark plug.
Ignition timing incorrect.
To check overall function of 3-way catalyst, start engine and drive vehicle at a speed of more than 43 MPH for 2 consecutive minutes. Stop vehicle and leave engine running. Measure voltage between engine ground and ECM terminals No. 50 (right front HO2S), or No. 51 (left front HO2S) and No. 56 (right rear HO2S), or No. 57 (leftrear HO2S) by backprobing. See Fig. 3 and Fig. 4. Increase engine speed to 2000 RPM. Switching frequency of rear HO2S should be less than 75 percent of front HO2S switching frequency. If operation is not as specified, go to
PROCEDURE. If front HO2S does not switch more than 5 times within 10 seconds, diagnose front HO2S first.
DTC P0505 Confirmation Test "A"
Malfunction is detected when IACV-AAC valve does not operate properly. Possible causes are: IACV-AAC valve circuit open.
Defective IACV-AAC valve.
To set DTC, turn ignition on and select DATA MONITOR with scan tool. Start engine and let it idle for at least 2 seconds. If first trip DTC is detected, go to PROCEDURE.
DTC P0505 Confirmation Test "B"
Malfunction is detected when IACV-AAC valve does not operate properly. Possible causes are: IACV-AAC valve circuit shorted.
Defective IACV-AAC valve.
To set DTC, start engine and warm to normal operating temperature. Turn ignition off and wait at least 5 seconds. Turn ignition on. Select DATA MONITOR with scan tool. Start engine and let it idle for at least one minute. If first trip DTC is detected, go to PROCEDURE.
1. Turn ignition off. Disconnect IACV-AAC valve harness connector. See Fig. 35. Turn ignition on. Measure voltage between ground and IACV-AAC valve harness connector terminal No. 2 (Yellow/Black wire). If battery voltage exists, go to next step. If battery voltage does not exists, repair open or short circuit and retest system.
2. Turn ignition off. Disconnect ECM harness connector. See Fig. 3. Check continuity of Orange/Blue wire between IACV-AAC valve harness connector terminal No. 1 and ECM harness connector terminal No. 101. See Fig. 4. Also check circuit for short to ground and short to voltage. Repair circuit as necessary and retest system. If circuit is okay, go to next step.
3. Measure resistance between IACV-AAC valve terminals. Resistance should be about 10 ohms at 68 F (20 C). Check IACV-AAC valve plunger for sticking. Also check for broken IACV-AAC valve spring. Replace IACV-AAC valve, if necessary and retest system. If IACV-AAC valve is okay, go to next step.
4. No problem is indicated at this time. Problem may be intermittent.