Technical MAP Sensor / Revs / TPMS / ESC / Hill-Hold

[2014Panda]

Evening all.

There is a fair amount of info. to give you I hope bullet points will make it easier.

FAULT SYMPTOMS:
- When idling and warmed, revs rise to 1500 and hold there. No further accelerator control.
- TPMS warning, ESC warning and Hill-Hold warning happen at the same time.
- TPMS valves were not fitted and are still not since we had the car in 2018 at 3.5 years old.
- Car drives fine at these fixed revs until...
- Switching off cures the problem until the next idle but ECU light remains on.
- ECU light goes off after the car has 24 hours of sitting and doing nothing.
- MAP Sensor fault confirmed with Pxxxx code by AA and another garage. Swapping MAP cured the problem all summer last year until today.
- Evidence of oil/water in breather pipe but no blockages. MAP sensor has a very slight sign of oil.
- Confirmed no HGF with pressure and chemical sniff test.
- No coolant loss.
- MAP connections all good. Loom good.
- Oil clean.
- Car does 10m on a dual carriage way to work and back each day.

I have read here there was a Fiat ECU update to reduce occurrences of fault like this but the rev. issue seems unique.
What about the idle valve is there is still one fitted to this age of car?

Ideas? Thoughts? The car has only done 27K miles.

A.

 

[Herts Hillhopper]

Two quick comments:

First up, no Panda has tyre pressure sensing valves. The system uses the ABS wheel sensors to ‘assume’ a low tyre pressure if one wheel is at a different speed to the others on a straight road.

And second: don’t believe any of the warning lights and OBD codes if the battery is anything other than 100%. Low battery voltage causes all sorts of odd messages and in turn affects the engine management. The engine light goes out after three on/off cycles of the ignition switch/startings of the engine if no further fault triggers it.

You say it’s ‘only done’ 27000 miles. And, I think you’re saying it’s a 2014 or 2015 car. If so, battery definitely on the way out. New battery about £100 (less if no stop-start) — that’s less than a garage bill to read the codes. (Several other posts here about effects if low voltages — including those in the ‘similar posts’ that appear at the bottom of this page)

If replacing the battery doesn’t cure it, then see posts about faulty brake light switch.

 

[2014Panda]

Many many thanks for the quick reply.

New battery fitted a year ago and before the first time this happened.

 

[2014Panda]

Two quick comments:

First up, no Panda has tyre pressure sensing valves. The system uses the ABS wheel sensors to ‘assume’ a low tyre pressure if one wheel is at a different speed to the others on a straight road.

And second: don’t believe any of the warning lights and OBD codes if the battery is anything other than 100%. Low battery voltage causes all sorts of odd messages and in turn affects the engine management. The engine light goes out after three on/off cycles of the ignition switch/startings of the engine if no further fault triggers it.

You say it’s ‘only done’ 27000 miles. And, I think you’re saying it’s a 2014 or 2015 car. If so, battery definitely on the way out. New battery about £100 (less if no stop-start) — that’s less than a garage bill to read the codes. (Several other posts here about effects if low voltages — including those in the ‘similar posts’ that appear at the bottom of this page)

If replacing the battery doesn’t cure it, then see posts about faulty brake light switch.

Is the fact the revs stay at about 1500 indicative of anything?

 

[jrkitching]

Is the fact the revs stay at about 1500 indicative of anything?

Does it respond to the throttle at all?

If it were mine, I'd put MES on it and see if there are any fault codes to be interrogated.

 

[Herts Hillhopper]

Is the fact the revs stay at about 1500 indicative of anything?

Sorry to say, I don't know! But, since you've already addressed the battery issue (and assuming its all still ok there), then see the second part of the suggestions (from others too) -- the brake light switch. As well as operating to turn the brake lights on when the pedal is pressed, it also activates a second switch to say the pedal is fully released. Its that second part that seems to lead to 'odd things'.

 

[2014Panda]

Does it respond to the throttle at all?

If it were mine, I'd put MES on it and see if there are any fault codes to be interrogated.

No response at all. Anti-stall means I can move OK in all gears.

 

[2014Panda]

This evening's update.

Drove the normal route to work along the DCW for 11.1 miles as normal. The 50mph section was done in 4th though. The idea being to heat the oil and get as much water vapour as possie out.

Tried to induce the fault by letting it idle on arrival. No fault. All well on the way back from work too.

Question. Have noticed the revs fluctuate when the car starts to move but in neutral, on a slops for example. Have also noticed the brake pedal can have the same effect. Is there an idle valve / actuator being told to do this? I know there is a connection between the clutch pedal and idle speed.

All interesting stuff. Would rather have SUs though.

 

[Tom95]

Question. Have noticed the revs fluctuate when the car starts to move but in neutral, on a slops for example. Have also noticed the brake pedal can have the same effect. Is there an idle valve / actuator being told to do this? I know there is a connection between the clutch pedal and idle speed.

Mine does this - but to a lesser degree. Only up to 1000-1100rpm for a couple of seconds. I believe that's a 'feature' of the Panda.

A high idle like that makes me think 'vacuum leak' but unlikely if it's only intermittent... Is there anything else odd about how the car drives when it's 'normal'?

 

[2014Panda]

Well, after a few days of all being well, it's done it again tonight. When idling in traffic for about a minute. It feels like the car has gone into a default mode to keep you moving. But no one here has said this is a design feature for when things go wrong. So, what can make the revs rise and hold perfectly stable at c. 1500?

 

[2014Panda]

PS. Brake light switch now replaced.

 

[The Panda Nut]

That B switch has a lot to answer for its tied to many things. The 1500rpm thing is almost certainly limp home mode. I have had a lot of silly issues caused by fouling of the MAP sensors on our 1.2 cars and both have catch cans fitted that fill up alarmingly quickly. I remove the throttle body occasionally and clean the manifold with a clean rag on the end of my claw pickup tool, and by doing this if running gets odd, have had no real issues since the catch cans were fitted. The last problem was caused by failing to empty said can and fouling started again.

 

[2014Panda]

That B switch has a lot to answer for its tied to many things. The 1500rpm thing is almost certainly limp home mode. I have had a lot of silly issues caused by fouling of the MAP sensors on our 1.2 cars and both have catch cans fitted that fill up alarmingly quickly. I remove the throttle body occasionally and clean the manifold with a clean rag on the end of my claw pickup tool, and by doing this if running gets odd, have had no real issues since the catch cans were fitted. The last problem was caused by failing to empty said can and fouling started again.

Is there an available diagram that locates the switch(es) and the idle motor/valve?

 

[ph81ds]

Hello, just wondering if the OP had any luck with the advice above?