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Measurement from phase to ecu, tips #1631533
07/04/2019 18:21
07/04/2019 18:21
Joined: Dec 2018
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Danmark
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denmark Offline OP
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Tips on how to measure the socket from cam phase sensor to ecu? 12v or 5v ohm? 3 pins. Cheers

Re: Measurement from phase to ecu, tips [Re: denmark] #1631534
07/04/2019 19:53
07/04/2019 19:53
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GrahamL Offline
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Pin #12 on ECU is black/white cable at ECU end, splits to 2 x green cables to power (+5v) cam sensor (pin #1) and throttle position sensor (pin #1)
Pin #8 on ECU is black cable, goes to cam sensor output (pin #2)

Pin #3 on cam sensor is black/white ground cable, connects to crank sensor + both knock sensor + lambda sensor grounds, then to main engine ground shared with loads of other stuff.

Given you were getting TPS and cam sensor errors it may be worth tracing the power (green) cables back from the TPS and cam sensors to the join where it becomes a single black/white cable and checking/re-soldering the original weld at that joint. Or could be the +5v power output driver from the ECU on pin #12 is failing when hot.

Maybe it's even possible that a bad TPS is failing when hot and somehow shorting or pulling down the +5v line which is then causing the cam sensor problem. When you get the error try disconnecting the TPS and then starting, to see if that clears the cam sensor problem.

Re: Measurement from phase to ecu, tips [Re: GrahamL] #1631535
07/04/2019 20:44
07/04/2019 20:44
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Fantastic Graham! You da man! Thank you for the great information, much appreciated. Best regards

Re: Measurement from phase to ecu, tips [Re: GrahamL] #1631540
08/04/2019 12:26
08/04/2019 12:26
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Cheers Graham, no output voltage on the b/w wire from ecu? Ignition on.. do the engine have to be running?

TPS sensor, no output on green with ignition on but on blue/red (pin 3) 5 volt??

Best regards

Re: Measurement from phase to ecu, tips [Re: denmark] #1631542
08/04/2019 12:43
08/04/2019 12:43
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GrahamL Offline
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I'm just going by what it shows in the service manual and wiring diagrams. It says TPS has +5v supply across pins #1 and #2, then outputs back to ECU on pin #3. And that pin #1 of TPS is also connected to pin #1 of cam sensor. Says it should be about 0.5v output from pin #3 of TPS with throttle closed.

Are you sure you have the correct black/white wire from ECU as there is probably more than one black/white on ECU plug. Was it definitely from pin #12 ? The engine can't start without the cam sensor so presumably the pin #1 on cam sensor will be powered from ECU just with ignition on but without starting.

Of course the service manual might be wrong, wouldn't be the first time. It does also say elsewhere that pin #2 of TPS is connected to "power supply for various sensors" which would suggest pin #1 on TPS is ground, but then why would it also be connected to pin #1 on cam sensor when cam sensor has a separate ground on pin #3 ?

Did you try disconnecting the TPS to see if it clears the cam sensor error and non-start?

Re: Measurement from phase to ecu, tips [Re: denmark] #1631544
08/04/2019 13:36
08/04/2019 13:36
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DaveG Offline
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The cam/phase sensor is a hall effect sensor and works by sending a pulse signal every time the cutout "slot" in the exhaust cam wheel passes over the sensor. The signal can be seen using an oscilloscope when cranking the engine, and it helps if you have a "break out" connector to measure the voltages. However, without an oscilloscope, if you remove the cam cover and locate the cam sensor, chances are it will be covered by the exhaust cam wheel, so take a measurement of the voltage on pin 2, then rotate the engine by hand and look for when the "slot" is over the sensor, and measure the voltage again. Check to see that you are getting a difference between the 2 measurements, that should hopefully confirm if the cam sensor is OK.


1996 Portofino 20vt & 2000 Pearl White Plus
1985½ & 2016 2017 Fiat 124 Spider + XF Sportbrake
Re: Measurement from phase to ecu, tips [Re: DaveG] #1631546
08/04/2019 14:55
08/04/2019 14:55
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Thanks Graham and Dave! Really appreciate all the inputs and help I can get.

Must say I am confused if pin 1 green on TPS should read 5v with ignition on.
Will try to get to socket and read the cam phase green wire.

Here's the error codes:

TPS

Anomaly on the throttle position signal, signal absent or inconsistent. Check the following:
- Ignition ON, sensor supply between pin 1 (+ 5 V,pin 12 ECU) and pin 2 (-) of the sensor connector
- Signal emitted from the sensor, proportional to the throttle position, on pin 3 of the sensor connector, the plug connected and ignition switched ON
- Continuity and insulation of the signal conductor, between pin 3 of the sensor connector and pin 53 of the ECU wires bundle connector
The reason for this fault is Unknown / No power supply
The current status of the fault is Impact occurred / Intermittent / Present
The error counter value is 65

Phase sensor:

The code is set when the Camshaft Position Sensor signal is missing. Possible causes are:
- Connector or wire problem in the signal circuit (open or short to 12V or ground)
- Sensor installed improperly
Check the connectors, wiring and proper installation of the sensor, and the signal waveform with an oscilloscope.
PLEASE NOTE: Certain systems always set this fault code as long as the engine is not running. This is not a sign of fault!
The sensor can be of inductive or Hall effect type.
The reason for this fault is Unknown / Short circuit
The current status of the fault is Intermittent / Present
The error counter value is 64

Re: Measurement from phase to ecu, tips [Re: denmark] #1631548
08/04/2019 15:30
08/04/2019 15:30
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TPS I get a read out of 5v between pin 1 and 3, also 5v from pin 3 to negative on battery.

Ecu bundle/socket I can only find one black/white wire or a thicker white/black.

But not sure if b/w goes to pin 12! Havent disassembled the connector.

Re: Measurement from phase to ecu, tips [Re: denmark] #1631551
08/04/2019 16:05
08/04/2019 16:05
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GrahamL Offline
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OK just checked on my own coupe to confirm...

Pin #1 of TPS does connect to pin #1 on the cam sensor and both are +5v with ignition on.
Pin #2 of TPS is ground
Pin #3 of cam sensor is ground

Therefore, pin #3 of TPS is signal output and pin #2 of cam sensor is signal output

That's with looking into the front end of loom side connector, holding it vertically with exposed spring clip part at right side, pin #1 is top, pin #3 is bottom.

Re: Measurement from phase to ecu, tips [Re: GrahamL] #1631555
08/04/2019 16:45
08/04/2019 16:45
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denmark Offline OP
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Thank you so much Graham! You have lead me on the right path. We shall celebrate when she up and running smile

Re: Measurement from phase to ecu, tips [Re: denmark] #1631556
08/04/2019 17:09
08/04/2019 17:09
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GrahamL Offline
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Should also mention, when I was testing it was with the connectors unplugged from the cam sensor and TPS sensor, just testing the output from the ECU and for +5v and ground, so not sure how the readings might change if the plugs were connected to the sensors.

Re: Measurement from phase to ecu, tips [Re: GrahamL] #1631558
08/04/2019 18:37
08/04/2019 18:37
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I tested unplugged also, will do a more in depth testing tomorrow on the wire from ecu to confirm if output.

How did you test the cam socket is beyond me smile not much space up there behind the engine.

Still don't got a clue why I get 5v output on pin 3 TPS and no output one pin 1 (green wire)..

You have been a real big help with your knowledge, thanks Graham.

Re: Measurement from phase to ecu, tips [Re: denmark] #1631587
09/04/2019 19:23
09/04/2019 19:23
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denmark Offline OP
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It was a dodgy new phase sensor! can't belive it only lasted a very short time in the garage..Thank you Graham for our dialog, I learned alot from you, know most of the wiring harness ecu and sensors etc. now smile

The TPS read 5v at pin 1 and pin 2 once I disconnected the phase sensor and knew something was up! Thanks for a awesome forum and the knowledge within.

Kind Regards from Denmark

Now back to get her up and running, the coupe haven't been on the road for 10 years and I have not even driven her yet! Hope it's gonna be a nice ride smile

click to enlarge



Last edited by Edinburgh; 10/04/2019 11:17. Reason: sorted pic
Re: Measurement from phase to ecu, tips [Re: denmark] #1631592
09/04/2019 21:35
09/04/2019 21:35
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GrahamL Offline
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Nice one, good luck with putting the engine back in. smile

Re: Measurement from phase to ecu, tips [Re: denmark] #1631596
10/04/2019 08:59
10/04/2019 08:59
Joined: Dec 2005
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Lightwater, Surrey, UK
DaveG Offline
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Oh, I didn't know the engine was out?


1996 Portofino 20vt & 2000 Pearl White Plus
1985½ & 2016 2017 Fiat 124 Spider + XF Sportbrake
Re: Measurement from phase to ecu, tips [Re: denmark] #1631597
10/04/2019 09:39
10/04/2019 09:39
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GrahamL Offline
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Looks "out" in the pic :

click to enlarge

Re: Measurement from phase to ecu, tips [Re: denmark] #1631598
10/04/2019 10:46
10/04/2019 10:46
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Lightwater, Surrey, UK
DaveG Offline
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Indeed it does, I couldn't get the pic to open earlier so missed it rolleyes


1996 Portofino 20vt & 2000 Pearl White Plus
1985½ & 2016 2017 Fiat 124 Spider + XF Sportbrake

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