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Chat Area => General Car Chat => Topic started by: terry paget on 14 April 2019, 18:05:58

Title: Code PO172-52 Fuel Trim System Lean
Post by: terry paget on 14 April 2019, 18:05:58

2006 Astra H 1.6 petrol
EML came on today, code PO172-52 popped up on reader. Is this just a glitch, or a serious problem?

Title: Re: Code PO172-52 Fuel Trim System Lean
Post by: JamesV6CDX on 14 April 2019, 18:08:45

Any air leaks?

Is the engine well serviced and running smoothly with no misfires?

If no air leaks and running ok it’s worth checking the maf readings

Title: Re: Code PO172-52 Fuel Trim System Lean
Post by: terry paget on 14 April 2019, 19:41:52

Quote from: JamesV6CDX on 14 April 2019, 18:08:45

Any air leaks?

Is the engine well serviced and running smoothly with no misfires?

If no air leaks and running ok it’s worth checking the maf readings

Only bought the car on Friday. Engine is running smoothly with no misfires. Thanks for advice, will check the maf readings tomorrow.

Title: Re: Code PO172-52 Fuel Trim System Lean
Post by: Nick W on 14 April 2019, 19:52:22

It's about time you started your own Youtube channel, Terry.


Instead of I bought the cheapest whatever in the country, you could call it I bought a faulty Astra. Again. Somehow :o

Title: Re: Code PO172-52 Fuel Trim System Lean
Post by: dave the builder on 14 April 2019, 20:53:13

Quote from: terry paget on 14 April 2019, 19:41:52

Quote from: JamesV6CDX on 14 April 2019, 18:08:45

Any air leaks?

Is the engine well serviced and running smoothly with no misfires?

If no air leaks and running ok it’s worth checking the maf readings

Only bought the car on Friday. Engine is running smoothly with no misfires. Thanks for advice, will check the maf readings tomorrow.

have a look at short & long term fuel trims ,front lambda switching , check the egr operates when revved 

Quote from: Nick W on 14 April 2019, 19:52:22

........
I bought a faulty Astra. Again. Somehow :o

can't be many faulty astras left near Terry , he's going to have to start looking further afield  :P

Title: Re: Code PO172-52 Fuel Trim System Lean
Post by: terry paget on 15 April 2019, 15:02:55

Cleared all codes last night, none have reappeared today. Pleased to read aircon pressure 120kPa, sounds good.  Otherwise:
EGR valve inactive
EGR position commanded 0
EGR position feedback 0.80 to 0.78

O2 sensor 1 rich/lean/rich/lean every 2 seconds or so
O2 sensor 2 lean

B1 short term fuel trim 0, varying between 4 and -4

I did not notice any mass air flow reading displayed.

Title: Re: Code PO172-52 Fuel Trim System Lean
Post by: TheBoy on 15 April 2019, 17:11:32

B1 Long term fuel trim?