2006 107 (Aygo) issue... Is it the battery?

[ekjdm14]

Hi all, just been to run PP2000 on my mum's little 107. It's an '06 plate with not quite 24k under it's belt and on it's original Fiamma battery(!)

The issue she'd had with it was a couple of times recently, after starting up it would (as I was told) refuse to go into gear/act as if the brakes were applied, accompanied by a warning beep sounding. After starting and moving the car down the driveway for better access I ran a diagnostic expecting to find plausibility or current draw issues with the MMG actuators, but the gearbox ECU was in fact clear and the only fault logged on the car was a power steering code C1541 "Vehicle speed sensor defective". I did note in the PAS parameters the voltage to ECU showed only 11.5 but DB tells me in the box that between 10-16v is fine(!) so I didn't pay much attention, although I had noted that it seemed to crank a little weakly I put it down to short journeys in winter and the fault code cleared fine.

After running the diagnostics KOEO I decided to get some temperature and actuator parameters from the gearbox with the engine running just to make 100% sure it was all moving smoothly, but would the engine restart? Nope! Flat as a fart, and the gearbox warning symbol popped on to boot!

Fortunately had jump leads so, while not ideal, we started it with the help of the GTi180 and kept it running just above idle as it wanted to stall otherwise. Finally get to do my KOER tests and all seems well with the gearbox but now the PAS fault (Same C1541 code) will not clear and I'm getting some funny readings from the voltage and current sense on the motor, plus it now does the warning beeper and refuses to move!

Personally I'm a little concerned about whether the PAS ECU is having a barney given the funny current/voltage readings (current flicking between -033A-invalid measurement regardless of input (ought to be -0.1A centred/no load and up to 34A full lock. Voltage on right turn =roughly same as ECU is getting (engine running it's seeing 14.2v at idle so alternator is charging nicely) but on left turn, even if I turned the wheel sharply it was only seeing 10.5v, and I did note turning left felt easier than right while stationary).

I have, however, left them with the advice to take it for a run out (after running for a while to charge the battery it went into gear fine and drove as normal just with the PAS lamp lit) and then get the battery checked/replaced and I'll pop back round and read/clear the codes again since I know how electronics hate brownout conditions like a dying battery. Just wondering if the PAS issue is likely caused by a weak battery or if I have some actual fixing to do too? Personally it makes sense it being battery related as it's electric PAS and I doubt the starter motor draws much more than that would being such a tiny engine, so I think it's got enough to start/run the engine (albeit if you "catch" it and don't let it stall for a minute!) but after that just doesn't have enough balls to keep powering the electronics AND provide for the steering's demands.

[doctle]

Test the battery I would, yoda

[ekjdm14]

Yep, fingers crossed a decent battery will yield results. Don't much like electric PAS but hopefully it'll be happier with good solid supply.

[GiveMeABreak]

I know on these Toyotas that the Power steering ECU relies on speed data sent by the engine ECU to determine the correct amount of assistance to supply. If you have the reg or the VIN Dan, I can have a squiz to see what I have on this for you.

[ekjdm14]

Thank You Marc, will PM you the reg in a sec. Don't have the VIN sadly but can ask if it's needed.

To be fair, I do feel it's a battery problem since the code went from intermittent to permanent in the time I was hooked up to the car & have had a report back from my mum letting me know that they went for a drive today in it to give it some use, and on startup the PAS light went out and no warning bleep/limp mode as yet. I know they (that generation of 107/C1/Aygo) have had their share of issues with the EPS though so it would be nice to have whatever info you have on the system just in case.

Will hopefully get back over that way some time in the next week to carry out a follow up session after the battery is changed/charged & will update on the situation then.

Thanks again Marc, much appreciated.