P0130 fault diagnostics

[Radio89]

Hi all,

SUMMARY:

• O₂ sensor malfunction code P0130
• Car self revving at idle, hesitant/ jerky in 1st and 2nd gear, sometimes surges when coasting in any gear and delayed throttle response at times.
• Replaced O₂ sensor (Aftermarket)
• Then started getting Lean codes. Fuel trims 33%
• Replaced MAF sensor, fuel trims hugely improved but still ~11 to 18% at idle
• Cleaned throttle body and adaption reset
• Addressed all visible vacuum leaks by smoke testing
• EVAP system not smoke tested
• Replaced fuel pressure regulator, now in spec. Not checked fuel trims since above repairs.
• Fuel pressure testing indicates no leaks. Therefore injectors should not be leaking? Injector resistances not checked (Power-balance)
• Back to getting O₂ malfunction P0130
• Crank sensor faulty, (related?)
• Am unable to get the car to rev at 2k rpm at idle, as it approaches 1900 it jumps to near 3k (related? Video attached. Bad throttle body? Bad throttle pedal sensor?)
• How do I test the O₂ sensor to find out if I bought a dud? (5 wire)
• What are my expected voltages and resistance values for the sensor and loom?
• Using VCDS Lite.
• 16514 - Oxygen (Lambda) Sensor B1 S1: Malfunction in Circuit
  
  P0130 - 35-10 - - - Intermittent
  
  16514 - Oxygen (Lambda) Sensor B1 S1: Malfunction in Circuit
  
  P0130 - 35-00 - -
  
  16555 - Fuel Trim; Bank 1: System Too Lean
  
  P0171 - 35-10 - - - Intermittent
  
• I need your help to come up with a solid plan of action and find this fault step by step.

https://youtu.be/0iomH5K2aYM

Could someone help me fault find a P0130 for a 5 wire O₂ sensor with calibration resistor B1S1 on an 2002 1.6L Audi A3 8L1 BFQ 8v engine. I originally got this code back in December shortly after purchasing the car so just for the sake of it I threw in a new one (Aftermarket) as based on manufacturers recommendations it was due for replacement after 80K. After replacement the light would come back on every 500 miles throwing a lean code this time and each time I would reset the check engine light. So after I got the light a few times I did some cursory diagnostics including: replaced MAF sensor, Cleaned throttle body, Replaced breather hose and oil filler housing, replaced a clamp on the the air intake hose which fixed all my vacuum leaks. Found my fuel pressure to be ~ 2 Bar so I replaced the fuel pressure regulator and now fuel pressure is back to spec at ~ 3 Bar.

Now instead of throwing a lean code I'm back to the malfunction in circuit P0130. If anything, the hesitation and surging have gotten worse which is great as it should make it that bit easier to find the fault. My symptoms have always been the car revving itself at idle between 800 and 1400 rpm. I will try to capture the condition on video if possible. I have to use the clutch to drag the revs back down to normal ~550 rpm. It used to only be when the car was hot after long journeys ~1 hour motorway driving but now it happens hot or cold. I can start the car cold and sometimes it will immediately idle at 950 or 1100 but my car should always idle at 550 regardless of temperature.

So if I no longer have any apparent vacuum leaks, my fuel pressure is correct and stable, the IM readiness monitors indicate pass for Evap then I conclude that I have one of 4 possible problems: A) I have an electrical fault with the O₂ loom (most likely), B) Faulty throttle body (plausible), C) Upper intake manifold is faulty, (likely), D) Evap system fault (plausible).

So ultimately I would like to test the O₂ sensor and the loom and require your help to identify if it is in fact faulty or one of the other systems are contributing to the fault. I should also note that when I start the car my rev counter has a fit for a second or two (displays 0 rpm during cranking and ~1 second of engine running. Again, will try to capture on video.) but always operates as normal from that point forwards. If I did my research properly then the rev counter takes it's signal from the crank sensor which should not affect timing advance, injection, or spark as these operate from the cam sensor. Correct me if I'm wrong. Perhaps the crank sensor is used for fuel mapping and is receiving bad intermittent information.


J

[Radio89]

Updated with specific codes.

[PoloMkIV]

P0130 Fixed on a 2006 1.2 VW Polo with a BME engine.
My son and also my apprentice at work have identical cars and both seem to exhibit the same fault P0130 Bank 1 Sensor 1 failure.
So I'm guessing this fault is quite common here is how I fixed my son's car. Hope it helps others, particularly my apprentice and his Dad who have spent many hours at this problem.

Bank 1 sensor 1 is the Lambda or O2 sensor on the top of the engine manifold just under the air filter that sits on top of the engine. Remove the filter box by gently pulling vertically and watch out for the little hose on the right hand side.

IMG_0891.jpg

The view above is taken when lying under the left-hand side of the car having removed the big plastic faring underneath by unscrewing the 6 Torx screws. I have unplugged the sensor wire and pulled it over to the center right just above ribbed tubing. The purple body of the connector leading to the sensor is visible in the center of the picture. Looking carefully you will see an area of damage in the black insulation where it crosses the ribbed tubing.

IMG_0897.jpg


Having carefully removed several inches of the black insulation we checked all 4 wires, only one was broken. Cut back the damaged wire till I got some reasonable copper & cleaned it carefully. Then soldered a new wire in and put heat shrink over the top. It is essential to maintain the twisting if as in our case it was a sensor wire that was damaged i.e not the heater wires. Though not my finest work I then taped it all up with new black tape from Halfords. New tape is nice and stretchy. I would suggest it is essential to solder the wires as simply twisting them together will fix the problem but will not last long in the winter weather.

Next using my OBD fault reader I reset the fault which didn’t want to go the first couple of times but did eventually reset. My son and I then went out for a 90minute drive with the fault reader connected. We made an effort to drive both fast and slow and sat and left the car idling for seven minutes which tripped the failure last time. All seems fine. Fault fixed.

LESSONS LEARNED
I did make the mistake of replacing the sensor before checking the wiring so that cost me £75 that I didn’t need to spend. I also noticed that the copper wire in the cable is heavily corroded though you would need a milli-ohm meter to detect wires still connected but "hanging by a thread". A normal meter will of course do for detecting "opens" or "shorts" BUT UNPLUG THE SENSOR BEFORE DOING THIS as I understand they can be damaged very easily if you put volts up the sense wires even from a multi-meter set to ohms!

Despite having taped up the cable and routed the wires carefully, if it goes again I will make up an entirely new cable and run it up to the EMU directly bypassing the cable loom all together. Let’s hope it does not get to that!

Best of luck.