OBD II P1555 2001 Vauxhall Vectra B


Some years ago I noticed an error light appearing on my Vauxhall Vectra B. This is the light with a picture of the car and a spanner not the outline engine. This light usually came on within 10 minutes or so of driving but never remained lit – each fresh start of the car it would be out. I was concerned at first but as there were no other symptoms and the car passed its MOT I tended to ignore it – especially as diagnostic work is expensive.

I came across an ECU error reader in Halfords and tried it – unfortunately it was for earlier cars (a fact not mentioned on the exterior but quite clear in the instructions inside) and had to be returned.

Recently I noticed some OBD II error code readers on eBay. Now all cars manufactured from 2001 on in the EU have to adhere to this standard but was mine manufactured in 2001? One seller had a picture of the OBD II socket showing which pins were used for each standard. Mine looked like it supported ISO 9141-2 so I took a chance and bought a Geniscan 300 which also supports the later CAN protocol.

My OBD II code
The scanner worked fine but showed no stored code. I had to leave it attached and rescan with the MIL on. I got a pending code P1555 which according to the code list software I got with the scanner is “Electronic Variable Orifice Output” for GM vehicles. After some work on Google this looked like a fault associated with the power steering which was working fine. I left the scanner on and checked regularly and always got the same code. On one occasion I had 3 codes – the P1555 as normal but also P1550 which was unlisted and a P1525 “Throttle Body Service Required“. As the other code was for a different car system I returned to dear old Google looking specifically for my codes with a Vectra”

The answer
After much searching I found a different interpretation of P1555 for the Vectra – “Throttle Position sensor/Mass Air Flow sensor – Implausible Signal” plus a possible solution – clean the throttle body and check for air leaks. I removed the plastic trunking from the air cleaner to the throttle body and sure enough the inside was filthy. A few minutes with some pieces of sponge soaked in methylated spirits and it looked pretty clean. After two weeks the light has stayed off – success – total cost scanner £40, sponge and meths – maybe £0.30, two plasters for cut finger and knuckle £0.40, half pint blood £0.00, various cleaning fluids to get filth from hands (unsuccessfully) £5.00. I’d advise using decent tools to undo the clips and take care with the butterfly – it’s very sharp. Plus wear some throw away gloves.



  4 Responses to “OBD II P1555 2001 Vauxhall Vectra B”

  1. Hi. Seems like you may have the same model as me as well as the same problem. Could you explain to me where exactly the ODB2 port was located? All google tells me is either right in front of the gearstick or in front of handbrake. But I can’t find it in either spot. Any help would be appreciated.


  2. It’s been a while back but so far as I remember on my Vectra B it was under a little plastic cover between the handbrake and gear lever. On my later Vectra C I think you had to pull out the ashtray. I have a Peugot diesel now so can’t check either.


  3. I’ll have a look again. The only plastic “cover” I can see seems to be a “horseshoe shaped” cover that goes from the “coincollector” right under the handbrake all the way to underneath the cover around the gear lever. I’ll pull out my ashtray and see if it may be under there.

    Did I understand correctly that the error you had was caused by a dirty airfilter?

    Thanks for your quick answer. :-)

  4. The connector location does depend on the model and the lights can appear for any number of reasons. For the code I got it wasn’t the aircleaner but the inside of the carburettor tube which was really black and filthy. Cleaning it got rid of the light in my case.

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