MAF P0102 fault

[juskavas]

Hi,I have a problem with my Seat Leon 2006 1.9 TDI (BXE).

Fault code:
P0102 – MAF signal too low.
Fault appears only when engine is running (comes back right after clearing).
MAF value is stuck at ~550 mg/str (doesn’t change with RPM).

What I’ve done:
Replaced MAF with new Bosch no change.
Checked wiring from MAF to ECU continuity OK.
5V reference present.
12V supply sometimes missing/intermittent.
Tried giving direct +12V and ground from battery still same problem.
EGR/DPF deleted long ago, no issues before.

What else could cause this? Wiring under load? Bad ground? Or ECU issue?
Thanks

 

[mty12345]

Could be a pin fitment issue. Maybe the connector terminals have been spread apart and arent contacting the MAF pins properly

 

[juskavas]

Could be a pin fitment issue. Maybe the connector terminals have been spread apart and arent contacting the MAF pins properly

Well, I changed the connector and checked the voltage again. It turned out there was no 12V (blown fuse). I replaced it — now everything is good. But pin 5, I guess, is the signal. When I test it with a multimeter (pin 5 to battery -), it shows 0.6–0.9 mV on the DC 200 mV setting, so basically nothing. I guess the signal wire is broken most likely. I will try to connect it directly from the ECU to the MAF.

 

[Frostensen]

I had a problem with turbo underboost for the longest time. Took turbo out and it came back without any malfunctions. It turned out that some random steering column errors (something that was often characterized as non important and minor by all mechanics) caused overheating of the electronics. That, together with a bad grounding caused system voltage drop that create ghost errors. If you want to check grounds, possibly try to push the car on the highway and turn on long beams as well open close windows. It should either cut the engine for a fraction of a sec. or cause lights flickering. If you have that, it may be that your problem is entirely caused by bad wiring.

 

[juskavas]

I’m not sure what the issue was, but I took apart the wiring harness – all the wires from the MAF to the ECU and to the fuse box were intact. I cut off the MAF connector and connected it directly with wires. It’s possible I shorted some wires while connecting them, which caused fuse 38 (10A) to blow. It had blown before as well, but after replacing it and connecting the MAF directly with wires, everything works. I then replaced the MAF connector, and everything continues to work fine. So I’m not sure what exactly was wrong – whether it was the connector itself or the fact that I moved the wires while taking everything apart.

 

[juskavas]

I had a problem with turbo underboost for the longest time. Took turbo out and it came back without any malfunctions. It turned out that some random steering column errors (something that was often characterized as non important and minor by all mechanics) caused overheating of the electronics. That, together with a bad grounding caused system voltage drop that create ghost errors. If you want to check grounds, possibly try to push the car on the highway and turn on long beams as well open close windows. It should either cut the engine for a fraction of a sec. or cause lights flickering. If you have that, it may be that your problem is entirely caused by bad wiring.

About Windows and lights. Sometimes the passenger window doesn’t work when I try to control it from the driver’s door. The button lights on the driver’s door also flicker and low beam headlights dim when I press the window switch, but I’m not too worried about that.

 

[Frostensen]

About Windows and lights. Sometimes the passenger window doesn’t work when I try to control it from the driver’s door. The button lights on the driver’s door also flicker and low beam headlights dim when I press the window switch, but I’m not too worried about that.

Yeah, lights flickering and low beam dimming when you press the windows switch is symptom for a grounding problem. Than can also deplete the battery in the long run, have that in mind as well.

 

[juskavas]

Yeah, lights flickering and low beam dimming when you press the windows switch is symptom for a grounding problem. Than can also deplete the battery in the long run, have that in mind as well.

Okay thank you