New throttle body but I still get P2135

[PeteS]

Having encountered the limp-home mode with "engine system fault, parking brake fault, DSC not available" messages on 3 occasions within 1000 miles on my 2007 3.0 S-Type Jaguar, I had a garage change the complete throttle body assembly. Having read in many posts and forums this part is eye-wateringly expensive, I was amazed to find it cost just £181 from Jaguar in the UK. By the way, it seems Jaguar re-designed the air-intake system on later models of this car, because the throttle body on mine is centrally located on top of the engine, away from any moisture source, whereas it's reported to be right at the back of the engine block on earlier models where it catches lots of rain run-off from the windscreen. However, in spite of replacing the throttle body, the fault came back again last week, 700 miles after the TB replacement. The DTC is P2135 - Accelerator pedal position (APP) throttle position (TP) sensor switch A/B voltage correlation". I'd be very grateful if someone could tell me what is likely to be still causing the fault condition.

[JOE-DOT-COM]

HI

That sounds like the most common fault on S-types

Low battery, will give all them faults, get the battery checked

If you can, get it on charge over night

cheers

Joe

[PeteS]

Thanks Joe.  I had read a weak battery can cause the symptoms.  I'll check it out.

[PeteS]

Had the battery and alternator checked and everything's good.  Also, the fault has occurred four times now and every time it's been after an hour or few hours of long-distance driving at motorway speed, so low battery doesn't seem to be a likely cause.  Is it easy to check the voltage output from the accelerator pedal position sensor or is it expensive to replace this part?  Would it make sense to do this?  I can't think what else to do.

[gourab]

I had the same problem. I changed my TB twice and it didn't fix the problem.
The problem was with the hose, specifically after the air filter. Check all the hoses after the air filter is in good condition and tightly secure all the clamps

Don't forget to go through a TB relearn process.

If this doesn´t fix your problem,
1. Check for any corrosion in the TB connector female ports. Clean it with a proper electric connection cleaner.

2. Check your battery power and alternator.
https://www.youtube.com/watch?v=LGB6ZEjGm7Q&t=10s
https://www.youtube.com/watch?v=BcGT1bNrsAM

[Wrinkly]

Please do not discount a discharging battery. S-Types are particularly susceptible to loss of battery charge. Mine will start doing sill things with codes etc if it is not kept regularly charged, even if being used on long runs. I have a CTEK 7.0 and make a point of having it charge the battery at least for 24 hours once per week. The battery is a 95Amp.Hr as recommended and is just 12 months old. I now do not suffer anywhere near as many silly codes and warning cropping up.

The submission concerning hoses is also very important, if in any doubt run or have run, a smoke test which will usually show up where there is any potential leak. In the "good old days", (excuse that but I am now 72 years young), we used to very sparingly use carburettor aerosol cleaner around the hose joints and listen for any increase in RPM. That would also give a good clue where the leaky hose was.

Good luck with correcing the proble.  Best Wishes and Regards, John