3 cyl turbo Clio

[studabear]

Relations car has thrown eml or check injection message on the dash. occasional a pig to start, extended cranking can take 3 or 4 times to start.

Scanned it today with Bosch KTS

P1525 CAN communication with the system <Cruise control> Unknown error type (F3)

P0340 Camshaft position sensor Signal plausability not OK

P0340 Camshaft position Sensor no Signal


The plausability code doesnt come back after a delete but the no signal one does as does can communication.

Unplugging the cam sensor with running or not doesn't bring any new codes or change anything.

Cam sensor has 3 wires with unplugged and engine running 1 wire is ground and 2 with 5v which google suggests is correct for sensor type

My Ancel PB100 can scope things I believe but I didn't have the equipment to back probe the wiring.

Going to hpefully order a new sensor tomorrow, as I'm fairly sure it will be that at fault.

Bosch Scanner won't show live data for cam or crank sensors so can't check that way, unless another scanner might do it.

Car is on less that 15000 miles with 1 owner and good history.

[OldGit]

You should be getting 5V on the sensor +ve supply and 4.5V or slightly lower on the signal wire, if it is 5V that would suggest a short or a failed control module.

[studabear]

I will double check the voltages before opening the new sensor box then.

Is that with the sensor unplugged engine running oldgit?

Thanks

[OldGit]

That's with ignition on, engine off & sensor unplugged.

The reason it should be less than 5V is so the control module can detect if the sensor is open circuit, short circuit (to either +ve or -ve) or giving a valid output.

You can test the sensor output connection by connecting to ground, which should give a DTC indicating as such, then connecting to the 5V supply, again, you should get a specific DTC - if you don't, that would indicate either pin grip, wiring or a control module issue rather than the sensor.

[chippie]

Stu, can’t you scope the signal wire on the cam sensor?

Should see a square wave with a time period of around 10mS with an engine speed of 3000rpm…..( 3000rpm is 50Hz, that equates to time period of 20mS, half engine speed would be 10mS…)

[studabear]

Need to be able to back probe it first Chippie. I believe the ancel pb100 can display a pattern/wave form

[Rhubarb]

Check condition of spark plugs

[studabear]

They were new last August as I serviced it then so in theory should be fine.

[studabear]

Been back to it briefly tonight after the gym. As oldgit stated I've rechecked what was at what pin with ignition on engine off.

Pin 1 5v
Pin 2 earth
Pin 3 4.5v

So is Pin 3 the signal wire?

I will order some back probes and try and scope this with the Ancel PB100 I that's the case and should hopefully confirm sensor is dead?


Thanks for the guidance with this btw. We don't really get too involved at work.

[Noberator]

Apr 3, 2023 18:39:37 GMT 1 studabear said:

They were new last August as I serviced it then so in theory should be fine.

Stu not wanting to say I'm teaching you how to suck eggs I'm not but never overlook the very basics it might or might not be something simple but how many times have we all been caught out diving in to deep when it's not needed.

[studabear]

I get that Pete, but it's constantly throwing the codes back up for no cam sensor signal. It does drive well enough and isn't misfiring.

Other issue is I'm having to run back and forward to have a look at it as and when I can. 🙂

[studabear]

Only other thing I can add is it does need a new battery which I will get fitted ASAP.

A Lucas EFB is in order.

[OldGit]

Yep, pin 3 is signal, scope it if you can, otherwise, a decent meter will give you an AC voltage reading, not a perfect diagnosis method but it will confirm or deny some sort of output.

The voltages you quoted suggest the ECM & wiring is OK.

These are the best backpinning probes i've found - not expensive either. www.picoauto.com/products/clips-and-adaptors/flexible-back-pinning-probe

[valhalla]

Apr 3, 2023 23:01:00 GMT 1 OldGit said:

Yep, pin 3 is signal, scope it if you can, otherwise, a decent meter will give you an AC voltage reading, not a perfect diagnosis method but it will confirm or deny some sort of output.

The voltages you quoted suggest the ECM & wiring is OK.

These are the best backpinning probes i've found - not expensive either. www.picoauto.com/products/clips-and-adaptors/flexible-back-pinning-probe

They are the ones I use for 90% of my work. They seem to take a bit of abuse without snapping, and even better is the pins that seem to stay shinier and less-tarnished than all the other kit, so the resistance measurements are always more reliable

[studabear]

A little update.

Replaced battery tonight with new Lucas EFB unit. Upon putting ignition on owner said all stop start unavailable, check injection messages and spanner light were on. It struggled to start first time as I wanted to check alternator was charging, it was. Switched engine off.

I then unplugged cam sensor and inserted a backprobe connector into cam sensor signal wire checked I had voltage reading at the back probe with ignition on engine off. Reconnected the sensor and he started the engine. Ancel appears to show a wave pattern, I'm not to familiar with these but I recorded a short video.

youtube.com/shorts/0julbvdQfIM?feature=share

So with the sensor giving a output I was feeling a bit stumped and already planning on asking further here.

Relation then said his radio was asking for code, so I got in drivers seat to find code and input it, did that and then put ignition on, started the engine Stop start available then flashed up, nothing about check injection and the spanner light was also off.

So I've told him to see how it goes for a few days and take it for a run before going home.

He messaged earlier to say its been fine.

Time will tell I guess, didn't have a scanner to immediate hand that would read beyond obd and to be honest it was pissing down and blowing a gale here on the coast, it would have been good to see if the error codes had gone from the ecu memory.