two days ago after pumping gas, I stared the car (2005 s type 3.0) and got message system failure with high idle speed, no gas pedal response at all and barely any brakes. Shut if off and restarted and it drove fine. Wife tooke it to work and reported to me that at freeway speed, it suddenly displayed system failure again and she got to side of road, shut it off and restarted and continued on her way. That night I read the codes and got one saying throttle position sensor "c" low voltage. Battery seems to be cranking fine but could this be as simple as replacing with a fresh battery?

ps....is it possible to program the dash display or touchscreen to show voltage? My obd tool shows it a 14.9 v at idle btw.

 

That's the alternator. Battery would need engine off (preferably for 8+ hrs).

What were the actual codes?

 

thanks for response. code was 0227

 

Guess you mean P0227. With a battery that has measured OK (not yet done), does it keep occurring?

Also worth doing a battery load test.

 

yes, p0227....I will pull the battery and get load test today. I hope it is not fuel pump failure, but can't understand why would the engine would go into system failure at cruise speed on the highway. But the car has a history of mysterious codes that imply various component failures that magically go away with a new battery. Kinda scary considering sending wife out on the road with symptoms like this.

 

Might in turn point to a drain that kills batteries. Some simple testing needed...

 

bench tested battery at auto zone. tested great under load. only code now appearing is p1000 which is due to incomplete evap that never goes away. car starting and driving ok, but fear of unknown cause of system failure is disconcerting. would it be adviseable just to replace the throttle position sensor? looks like just a harness and 2 bolts? prices online around $30.

 

Well evap should complete so that points to a fault.

Caution - throttle looks likely to mean accelerator pedal for this. Be sure...

 

jagv8.....you may recall months ago you participated in helping troubleshoot a code 0174 (lean bank 2) that was preventing me from passing a smog. I eventually got a smog guy to test and pass it with evap still incomplete. It has been years since I got a successful all clear obd. Evap refuses to complete.
I am not sure what you mean about accelerator pedal..be sure???
Are you thinking that the P0227 is related to accelerator pedal? How do I test that? Thanks for help.

 

Jag code PDF says it's APP. You can look it up yourself but be sure to check Jaguar's own doc.

 

Jagv8....looked at the gas pedal and position sensor attached, and found the assembly to be loose and moving slightly as a whole when the pedal is moved. There is a 10mm bolt with nylon washer on the side (pictured) that appears to be stripped out,as it just spins and spins when I try to tighten it. Could this be a factor?
Also, on the driver's side of throttle body, there is a black plastic thingy with a wire harness plug that a 2-wire harness clips onto, however the plug clip is broken off and the harness is not secured via clip. It is however, firmly on and would take effort to slide off. So what is that black plastic thingy on the driver side throttle body and what does it do.? Can that part be purchased separately and bolted on?

 

I don't know about buying such. I don't even have your specific model.

I can only refer you to Jaguar doc and what they say.

With no TPS code but instead an APP one I'd deal with the one that's actually there.

 

Just to point out that my 03 STR when purchased , had an accelerator pedal position senser code and turned out to be water in the TPS plug as so many Early STR had problems with , causing limp mode and multiple message center faults displayed . I relise it a differant model ,and the v6 will have trouble even getting water close to the plug on the TPS unless washing the engine ! but still well worth looking inside the plug for clues , as these plugs have vents and are not sealed . I never replaced a thing relating to the problem , just cleaned it out, wire brushed the corrosion and sprayed wd40 in there and silicon sealed the plugs vents and wires, no probs since ! Not saying it's not the EPP , but check all avenues before purchasing these expensive parts . I definatly got lucky on that one !

 

Yes but
1. STR has TPS in a different place and that's prone to water
2. does not appear to be a TPS code but an APP one!

 

So what should I do here? Have test driven a few times since this last occurred and have not had repeat and no code popping up. If P0227 is specifically the accelerator position sensor ( I take that to mean the accelerator rheostat assembly that the gas pedal attaches to), then should it not be driven until that assembly is replaced? Or is there another sensor I should be looking at?

 

It's a dual sensor (see the workshop manual) so worst case it can tell there's a fault and go restricted. If you can live with that I'd drive it.

 

Jagv8...I do appreciate your continued help , please understand I am a do it yourselfer, not a professional. I don't have a jag workshop manual and the multiple diagnosis for multiple symptoms with these cars is very confusing. This is wife's transportation and I know I could just keep replacing one component after another or go buy a new car (I can't). Aside from worry about her becoming stranded on the roadside, is it possible or likely that the accelerator could become frozen in accelerate position while driving?

 

I have attached a message from Jag regarding the evap test that is not being completed with details on how to get it to complete. There are 2 that need to be done and it is the second one that you need to follow instructions. I have had the same problem before and this has solved it every time.

Tom in Dallas/Plano
05 S-0type 3.0 91k