Why not unplug those 2 again.. see if you get 1 minutes running..
IF it does run.
Unplug just one at a time.
See which one makes the improvement.
You need better diagnostic kit.. but this should give you some info while you wait for the postman
Technical starts then cuts out
- Thread starter chr1sd
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Technical starts then cuts out
Why not unplug those 2 again.. see if you get 1 minutes running..
IF it does run.
Unplug just one at a time.
See which one makes the improvement.
You need better diagnostic kit.. but this should give you some info while you wait for the postman
Why not unplug those 2 again.. see if you get 1 minutes running..
IF it does run.
Unplug just one at a time.
See which one makes the improvement.
You need better diagnostic kit.. but this should give you some info while you wait for the postman
Ok im still waiting for the MES cable to be delivered. in the meantime if had another look today. so had the car running again today, without touching the throttle it car cold idles, but when you give it some throttle it goes lumpy and and doesnt rev. I disconencted the MAp and the Camshaft sensor and it made no difference to the running of the car. looking on my diagnostic machine, the MAP reading is 0 constantly.
So i went about looking at the wiring. using the Wiring diagrams and pinout from Elearn, i checked continuity between all the sensor connections and the corresponding Ecu Pins on plug B. They all check out ok, so:
Map Sensor:
pin 1 to pin 7 on ecu
pin 2 to pin 63 on ecu
pin 3 to pin 13 on ecu
pin 4 to pin 31 on ecu
CAmshaft sensor:
pin 1 to pin 7 on ecu
pin2 to pin 24 on ecu
pin 3 to pin 13 on ecu.
Heres the strange thing though. According to the elearn wiring diagrams etc, Pin 13 on ECU is the +5v supply for both these sensors, but with ignition on no engine running, I am getting +5v on pin 2 of the Map sensor and pin 2 of the camshaft sensor.
going off the elearn document:
pin 2 on map to oin 63 on ecu is the signal connection for map sensor
pin 2 on cam sensor to pin 24 on ecu is the signal connection for Cam sensor.
Does anyone know if this is an error on the wiring diagram or is my ecu outputting incorrectly, as the wiring pinouts are correct. im confused now :bang: its as if the signal connections and the 5v supply connections at the sensors are back to front.
chr1sd
Take a few minutes, read this a few times, watch a few youtube videos , come back and read this again:
You need to be more specific about testing procedure:
-did you test with sensors connected/disconnected?
-did you back pin the sensors/ or probed the wires?
-did you use a small (10w bulb) load when measuring?
-engine off/ or running?
Without knowing any of these.. i'm just going to guess: bad ground (at least to those sensors)
5v on MAP signal wire could mean there is no ground to the sensor, so no part of the voltage is being pulled to ground => full 5v
(the camshaft sensor ..it's just a magnetic switch...it goes on/off depending when the cap slot comes by it)
(it can be continuously ON, and metal turns it OFF, or it can be the other way around continuously OFF and metal close to it turns it ON)
If you had MES it would say something like this:
Circuit error, signal high. (this means no/or bad ground)
Circuit error, signal low. (this means low /no reference circuit..or internal sensor fault)
MES would tell you so much after you get used to it a bit... it's just a tool=> you still need to know how to use it.
Take a few minutes, read this a few times, watch a few youtube videos , come back and read this again:
You need to be more specific about testing procedure:
-did you test with sensors connected/disconnected?
-did you back pin the sensors/ or probed the wires?
-did you use a small (10w bulb) load when measuring?
-engine off/ or running?
Without knowing any of these.. i'm just going to guess: bad ground (at least to those sensors)
5v on MAP signal wire could mean there is no ground to the sensor, so no part of the voltage is being pulled to ground => full 5v
(the camshaft sensor ..it's just a magnetic switch...it goes on/off depending when the cap slot comes by it)
(it can be continuously ON, and metal turns it OFF, or it can be the other way around continuously OFF and metal close to it turns it ON)
If you had MES it would say something like this:
Circuit error, signal high. (this means no/or bad ground)
Circuit error, signal low. (this means low /no reference circuit..or internal sensor fault)
MES would tell you so much after you get used to it a bit... it's just a tool=> you still need to know how to use it.
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I disconnected the plug from the sensor and measured the voltage being supplied to each of the pins at connector. I continuity checked all the pins on sensor connectors back to ecu connector and they matched the wiring diagram in elearn. As per that video, I would expect on a 3 wire sensor the outer pins would be positive and earth as per elearn diagrams, but was getter earth on pin 1 and 5v on pin 2. If the sensor was connected I could understand that the sensor may have switched the 5v to signal wire giving its current state, but with no sensor connected, I would have expected the voltage at the connector pins would be the voltage being supplied by the ecu. Ie why would the ecu be supplying 5v to a pin which is showing on a wiring diagram as a signal wire? This isn't a sensor or wiring issue as I'm getting the same readings at ecu connector when back probing the pins to engine ground. So pin 13 which is supposed to be 5v supply to both sensors is getting no voltage. Pins 63 and 24 which are supposed to be signal 'in' pins from the sensors are both giving out 5v on each pin.
My wife has a 500 with same engine /ecu, so I am going to check and compare hers today.
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First of all: measuring with a DVM with sensors unplugged isn't great.
You need to measure in parallel with a small load. A 5w bullb... just go to a parts store... or supermarket and buy a 5-20w 12v bulb, one that you can easily attach 2 wires... and use it to check for current flow (meaning the bulb will light up)...and in parallel with DVM check for voltage.
5V on a signal wire with sensor disconnected, and no load... that can just be the way the ECU detects if a sensor is connected. Either way i would ignore the no load reading.
If you have 5v measured in parallel with a load... that might be a problem but i would still ignore it for now.
Focus on the 5v power supply.
Make sure you use a good ground point (eliminate it as a variable)
If you have no 5V that could mean a short to ground( Voltage is being pulled to ground so wire or sensor).
Are the cam sensor and the map sensor the only 2 sensors on this 5v rail?
You can have multiple pins on the ECU that all deliver 5v to various sensors, BUT they can be all connected inside the ECU..so basically one big 5v rail.
Some ECUs have one 5v rail, some have 2, some have more.
Check some other sensors for 5v.
If you do find another 5v you can bridge it to this 5v rail (one wire from one connector to another) and check if it will be instantly pulled to ground => 0v (BUT you would also have to remove pin 13 form the ECU connector). If voltage falls to ground there is a short in wire/sensor somewhere and ECU is fine ( might be able to measure 5v on the pin inside the ECU).
You need to measure in parallel with a small load. A 5w bullb... just go to a parts store... or supermarket and buy a 5-20w 12v bulb, one that you can easily attach 2 wires... and use it to check for current flow (meaning the bulb will light up)...and in parallel with DVM check for voltage.
5V on a signal wire with sensor disconnected, and no load... that can just be the way the ECU detects if a sensor is connected. Either way i would ignore the no load reading.
If you have 5v measured in parallel with a load... that might be a problem but i would still ignore it for now.
Focus on the 5v power supply.
Make sure you use a good ground point (eliminate it as a variable)
If you have no 5V that could mean a short to ground( Voltage is being pulled to ground so wire or sensor).
Are the cam sensor and the map sensor the only 2 sensors on this 5v rail?
You can have multiple pins on the ECU that all deliver 5v to various sensors, BUT they can be all connected inside the ECU..so basically one big 5v rail.
Some ECUs have one 5v rail, some have 2, some have more.
Check some other sensors for 5v.
If you do find another 5v you can bridge it to this 5v rail (one wire from one connector to another) and check if it will be instantly pulled to ground => 0v (BUT you would also have to remove pin 13 form the ECU connector). If voltage falls to ground there is a short in wire/sensor somewhere and ECU is fine ( might be able to measure 5v on the pin inside the ECU).
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I am getting correct 5v at throttle body, and only 1.5v approx at crank sensor. I have struggled to find a proper wiring diagram to look at what sensors share supplies, just looking at the pinout listings on elearn.
My mes cable should be here today so can have a look at that. I'm going to compare the readings on the wife's 500 this morning. Will update later today
Got the MES cable through post. did a throttle calibration which seems to have got rid of the throttle error and watching the pedal position in MES moves smoothly from 0-5v so pedal working ok. cleared the codes out and straight away its picking up the Sensor 5v reference voltage problem before turning it over.
so there's either a bad sensor pulling all the load, wiring issue between ecu and sensors or duff ecu. i'm planning on checking the 5v reference voltage straight out of the ecu without the engine side loom connected. To be honest, im hoping the voltage is wrong there so i can just replace the ECU, save me checking the loom :bang: see how i get on at weekend.
so there's either a bad sensor pulling all the load, wiring issue between ecu and sensors or duff ecu. i'm planning on checking the 5v reference voltage straight out of the ecu without the engine side loom connected. To be honest, im hoping the voltage is wrong there so i can just replace the ECU, save me checking the loom :bang: see how i get on at weekend.
Well the saga continues. MES shows the following errors. I have replace the loom from ecu to engine / sensors & Ecu to fuse box with a known good ones, and fault remains. i am getting 10v at pin 13 of the ecu with the loom disconnected, which is the sensor supply voltage. with the loom connected, ignition on, if i back probe the cam sensor, i am still getting 5v at pin 2 and 0.4v at pin 1. the wiring diagram states it should be 5v at pin 3 and signal at pin 2.
So 2 different looms, new cam sensor and still the same start issues and MES codes. Only thing i can think of is a duff eCU. any other ideas?
P0651-16 Sensor Reference Voltage B
P0340-15 Phase sensor
So 2 different looms, new cam sensor and still the same start issues and MES codes. Only thing i can think of is a duff eCU. any other ideas?
P0651-16 Sensor Reference Voltage B
P0340-15 Phase sensor
Hi,
What is the voltage at pin 3 with the sensor connected and what are you connecting the meter negative to?
A useful set of readings would be
Ignition ON engine OFF, sensor and ECU connected
With meter negative to battery negative:
Voltage on sensor pin 1
Voltage on sensor pin 2
Voltage on sensor pin 3.
AND
With meter negative connected to sensor pin 1
Voltage on sensor pin 2
Voltage on sensor pin 3.
Does sound like an ECU Fault. While I agree with aurick86 that testing with some load is a good idea, a 5W (never mind 20W) lamp is too much load for a ECU sensor supply In particular the resistance of the lamp is much lower at 5V than 12V and it's even lower when cold. This puts a near short circuit on the sensor supply. This may cause damage ot the ECU. For example just unplugging and re-connecting the tank unit an a Croma (and some Puntos that have similar circuits) can damage the ECU causing the fuel gauge to fail.
Robert G8RPI.
Hi,
What is the voltage at pin 3 with the sensor connected and what are you connecting the meter negative to?
A useful set of readings would be
Ignition ON engine OFF, sensor and ECU connected
With meter negative to battery negative:
Voltage on sensor pin 1
Voltage on sensor pin 2
Voltage on sensor pin 3.
AND
With meter negative connected to sensor pin 1
Voltage on sensor pin 2
Voltage on sensor pin 3.
Does sound like an ECU Fault. While I agree with aurick86 that testing with some load is a good idea, a 5W (never mind 20W) lamp is too much load for a ECU sensor supply In particular the resistance of the lamp is much lower at 5V than 12V and it's even lower when cold. This puts a near short circuit on the sensor supply. This may cause damage ot the ECU. For example just unplugging and re-connecting the tank unit an a Croma (and some Puntos that have similar circuits) can damage the ECU causing the fuel gauge to fail.
Robert G8RPI.
Thanks. I've tested both ways taking earth from battery and pin 1, makes no different. Voltage at pin 2 with sensor connected (back probed) and ignition on is 5v. Voltage at pin 3 is approx 0.2v.
If I back probe the ecu connector in the same state, pin 13 which is supposed to be the 5v out is 0.2v and the sensor signal pins on ecu are 5v.
The reference voltage error in Mes is instant. So if I clear the codes, it remains without even starting the engine.
Hi,
What are the part numbers on the sensors? Actually on them, not what you ordered.
Robert G8RPI.
Cam - 55228528
Re: starts then cuts out - **FIXED**
Well after all the time and money the previous owner put into the car with Auto electricians etc, and the time i spent tracing wiring harnesses and using MES to trouble shoot sensors, I went ahead and bought a replacement ECU off ebay (recoded for my car) and problem solved. car started straight up, no errors, runs sweet.
So as per my previous posts, looks like the ecu was outputting supply and signal voltages incorrectly. So now onto the work to get it through the MOT. definitely needs new springs as both fronts are snapped.
Heres a picture of the trouble maker.
Thanks for all the tips and advice
Well after all the time and money the previous owner put into the car with Auto electricians etc, and the time i spent tracing wiring harnesses and using MES to trouble shoot sensors, I went ahead and bought a replacement ECU off ebay (recoded for my car) and problem solved. car started straight up, no errors, runs sweet.
So as per my previous posts, looks like the ecu was outputting supply and signal voltages incorrectly. So now onto the work to get it through the MOT. definitely needs new springs as both fronts are snapped.
Heres a picture of the trouble maker.
Thanks for all the tips and advice
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Well done to you..perseverence is the key...outta interest what did the 'new' ecu cost?..
It was £70 Inc coding to the car. Off ebay.
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Great result..
Im often left thinking that the act of phsically swapping an ECU is enough to sort poor connections.etc.
But your systematic approach has been an eye opener.
Top job. !!
Lets hope the machanical stuff is nice and simple.
Charlie
Im often left thinking that the act of phsically swapping an ECU is enough to sort poor connections.etc.
But your systematic approach has been an eye opener.
Top job. !!
Lets hope the machanical stuff is nice and simple.
Charlie
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