RAC mis-diagnosis cost me £369

Brenners Posts: 2 Newbie
First Post
After RAC attended a call out I sent the following (redacted) letter to their Complaints Department.

On December 25
th I had need of your service, but being Christmas Day, I waited until December 27th  before calling you out, as my vehicle was safely parked on my drive and there would have been many of your customers in much more urgent need than I.

Your patrolman arrived without much of a delay and was very professional. After a visual check showed nothing amiss, he started the engine and it raced up to 3,500 RPM and he immediately switched off. He then plugged in his diagnostic computer which showed that the Throttle Position Censor was at fault. Under his advice, I purchased the sensor, which came as a complete throttle pedal assembly, and as it was only a matter of two bolts, a nut and an electrical plug, it was agreed that I would fit it to the car.

On starting the engine, after fitting the part, the fault was still there, racing up to 3,500 RPM. I turned off the ignition and called the RAC and explained the situation. Another patrolman quickly arrived and I explained what had happened. He plugged in his computer and it came up with the same fault. I confirmed that the throttle assembly was an original Kia part and he methodically checked everything he could think of that might be the cause.

After running out of ideas, he called your technical team and eventually they found someone that had came across a similar problem. It was suggested that one of the drainage pipes from the sunroof had blocked, causing water ingress through the nearside ‘A’ pillar and into the passenger compartment, seeping under the carpet and soaking the ECU and its connections. He dried out the plugs and wiring into the ECU and it cured the problem.

My point is that I ordered and paid £369 for the part, in good faith and on the advice of your patrolman – which, being an electrical item, is non-returnable. Had I been unable to fit the part, your patrolman would have sourced it from Kia and fitted it, and I doubt the RAC would have charged me for it, as the original part was not faulty.

The second patrolman said that he would mention the fact that I had paid out for this item that was not needed and he would send me a copy of his report which has not yet arrived.

As a pensioner, I would appreciate it if you could look into this to see if anything can be done regarding reimbursement of said unnecessary expense.

I received the following reply.

I'm very sorry to hear your account of events after you broke down on 28 December 2023

We pride ourselves on providing a first-class service, both on the phones and on the road, so it's always disappointing to receive reports like yours.

I sincerely apologise if you felt our first Patrol didn't provide the level of service you'd expect of us. An expert technician has investigated your case and found there is not enough evidence to suggest our Patrol misdiagnosed the repair. The diagnostic trouble codes recorded on your vehicle's onboard computer during our attendance on 28 December show a code listed as follows

DTC: P0220, Throttle/Pedal Position Sensor/Switch B Circuit Malfunction.

When RAC reattended on 4 January 2024, there were additional fault codes recorded, suggesting a different fault was now present following you fitting the throttle position sensor.



Name: D4CB-2,5 WGT

DTC: P0220, Throttle/Pedal Position Sensor/Switch B Circuit Malfunction

DTC: P0190, Fuel Rail Pressure Sensor Circuit Malfunction

DTC: P0120, Throttle/Pedal Position Sensor/Switch A Circuit Malfunction

DTC: P0403,Exhaust Gas Recirculation Circuit Malfunction

DTC: P1180, Oxygen-sensor heater 1

In view of this, we're unable to accept liability for this claim. I appreciate this isn't the response you wanted, but I hope you can see from this information how we came to this decision.

Our complaints process has now come to an end and this email is our final response. We will not be entering into any further correspondence. Once again, I am sorry that you have had cause to complain.


(Obviously, to me, more water, it took a week for the part to arrive, means more fault codes, which were cleared after the patrolman dried out the ECU connections, then all was well).

Has anybody any advise as to what I should do next.


  • pogg000
    pogg000 Posts: 552 Forumite
    First Anniversary First Post
    DTC's only point you to the area of cause. You should check wiring/ supply voltage and signals before replacing random parts
    lbm 11/06/12 dept total 11499.47
  • Ayr_Rage
    Ayr_Rage Posts: 1,014 Forumite
    First Post First Anniversary Photogenic Name Dropper
    edited 7 March at 4:45PM
    DTC: P0220, Throttle/Pedal Position Sensor/Switch B Circuit Malfunction.

    The fault could have been anywhere in that circuit rather than just the unit you replaced.

    Unless you have it in writing that the first technician positively identified the faulty part and told you to buy a new one then I think you have no chance of the RAC reopening your complaint.
  • Mildly_Miffed
    Mildly_Miffed Posts: 311 Forumite
    First Post Name Dropper First Anniversary
    Apart from anything else - drying everything out cleared the symptoms.

    Have you cleared the sunroof drain? That's the cause... Unless and until you do that, you'll just get more water ingress.

    I'd have said the RAC went above and beyond - the service you expect (basically, a mobile mechanic for diagnostics) is explicitly not what the At Home is for.
  • Spies
    Spies Posts: 2,028 Forumite
    First Post Photogenic First Anniversary Name Dropper
    Sell on the un-needed part? 
    4.29kWp Solar system, 45/55 South/West split in cloudy rainy Cumbria. 
  • Goudy
    Goudy Posts: 1,485 Forumite
    First Anniversary First Post
    edited 8 March at 8:45AM
    It's a fairly reasonable assumption to make, that the DTC related to a throttle position sensor fault but not necessarily a faulty throttle position sensor.

    I don't doubt other garages and even dealers would not make the same assumption initially, it's what you should do after that where things went wrong for you.

    The patrolman could have thought you would take it to a garage and ask them to explore the throttle position sensor problem further, as they would likely be in a better position to do that than the patrolman out on the street.

    It sounds like the patrolman read the ECU codes and told you it's a throttle position sensor fault (not a faulty throttle position sensor) which with the P0220 code most people would tell you.

    You have then taken that to mean the throttle position sensor it bad and replaced it rather than investigated the problem further.
    Unfortunately that was your decision.

    You only have to to a quick search of the DTC P0220 and virtually all the results will tell you that there are a list of many causes, only one being a faulty throttle position sensor.

    The diagnoses process should have started with the easy and free checks but even after those, you'd still need to confirm if a part has a problem, particularly if it's expensive before replacing in hope.

    As you have found out, the replace in hope generally works out more expensive than proper diagnostics.

    A bit late now but the best way to think about what a DTC means is to think of it as a symptom first rather than a fault in itself.
  • MEM62
    MEM62 Posts: 4,746 Forumite
    First Anniversary Name Dropper First Post
    edited 8 March at 11:59AM
    Interesting isn't it that people seem to think that vehicle diagnosis is an exact science. It isn't.  When my Triumph Bonneville developed a starting problem it went back to Triumph three times (luckily, under warranty) before it was correctly diagnosed.  On each occasion to RAC checked it the fault code indicated a problem with the ECU - which was replaced but did not solve the issue.  Eventually, the fault was traced to faulty throttle bodies that were not cycling properly during the start-up routine, thus generating an error code that caused the ECU to shut down.  Modern vehicles are complex and the more complex they are the more elusive faults can be. 

    @brenners I don't think you have any comeback against the RAC, they reported the fault code that they found but, as we know, this does not always pinpoint the issue.    

  • Brenners
    Brenners Posts: 2 Newbie
    First Post
    The RAC patrol men did go above and beyond, I agree. My point is that they both said it was the throttle position sensor that was at fault and even explained that there are two potentiometers in there and both must be faulty, and as I said, I bought the throttle assemble on the advice of the first patrolman and didn't just replace 'random' parts. 
    Had it been a good, old fashioned, sticking throttle cable, broken spring or a loose connection, I would have diagnosed it and fixed it myself. 
    In my ignorance, I thought that modern cars, with their electronics and computers, diagnosing faults would be an exact science. Apparently not. I wouldn't know how to check the sensor but from what has been said here, the patrolman should have checked it.
    The sunroof drains are now clear and the carpets are dry and the spare throttle assembly will now be going on Ebay.
    I'd just like to say that in nearly 60 years of fixing and servicing my own cars, I've had to use 'professionals' twice, once to replace and oil seal and bearing on a Mk1 Escort half shaft and once to find out way my engine raced to 3,500 RPM on start-up, both times I got ripped off.
    C'est la vie.
    Thank you for your comments and this is where the story ends.
  • Mildly_Miffed
    Mildly_Miffed Posts: 311 Forumite
    First Post Name Dropper First Anniversary
    Brenners said:

    In my ignorance, I thought that modern cars, with their electronics and computers, diagnosing faults would be an exact science. Apparently not.

    The ECU knew that it'd received a dodgy message from the throttle position sensor, so recorded that information. It has no way of knowing if that's because of a dodgy sensor or dodgy wiring.

    In this case, it turned out to be dodgy wiring, due to a sunroof drain that should have been cleaned as part of routine maintenance.
Meet your Ambassadors


  • All Categories
  • 343K Banking & Borrowing
  • 250.1K Reduce Debt & Boost Income
  • 449.6K Spending & Discounts
  • 235.1K Work, Benefits & Business
  • 607.8K Mortgages, Homes & Bills
  • 173K Life & Family
  • 247.8K Travel & Transport
  • 1.5M Hobbies & Leisure
  • 15.9K Discuss & Feedback
  • 15.1K Coronavirus Support Boards