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Ford Mustang 2015 5.0 TiVCT V8 - P0390 & P0394 - Camshaft position sensor B circuit intermittent (bank 2)
Ford Mustang 2015 5.0 TiVCT V8 - P0390 & P0394 - Camshaft position sensor B circuit intermittent (bank 2)
Ford Mustang 2015 5.0 TiVCT V8 - P0390 & P0394 - Camshaft position sensor B circuit intermittent (bank 2)
Condition: KOEO
DTCs: P0390 & P0394
Result: Runs fine, but reports DTC-s above.
What I have done
Used Pico to scope and graphed CMP12 and CMP22 (the one referenced in the DTC) and CKP. All sensors 2 pin inductive. Graph in attachments.
Measured the capacitance of the ignition transformer capacitor - 250 nF.
What I see
I do see noise spikes on all 3 channels, on CKP very little, but on both CMP-s very notable.
Noise correlates to ignition firing events - for 720 degrees of crank rotation I get 8 evenly diatributed spikes in the sensor signals.
I disconnected one coil, and lost one noise spike, which confirms once again that the spikes are related to ignition events.
Questions
1. What could cause ignition events causing the noise?
2. What else to check?
3. How to fix the issue?
All the best!
Condition: KOEO
DTCs: P0390 & P0394
Result: Runs fine, but reports DTC-s above.
What I have done
Used Pico to scope and graphed CMP12 and CMP22 (the one referenced in the DTC) and CKP. All sensors 2 pin inductive. Graph in attachments.
Measured the capacitance of the ignition transformer capacitor - 250 nF.
What I see
I do see noise spikes on all 3 channels, on CKP very little, but on both CMP-s very notable.
Noise correlates to ignition firing events - for 720 degrees of crank rotation I get 8 evenly diatributed spikes in the sensor signals.
I disconnected one coil, and lost one noise spike, which confirms once again that the spikes are related to ignition events.
Questions
1. What could cause ignition events causing the noise?
2. What else to check?
3. How to fix the issue?
All the best!
- Attachments
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Re: Ford Mustang 2015 5.0 TiVCT V8 - P0390 & P0394 - Camshaft position sensor B circuit intermittent (bank 2)
Hi Tiblu,
Please take my comment as generic only, I don't touch US or Japanese cars which are using inductive sensors, but some our European cars have them also.
So here is my comment, hope it helps or give you new ideas.
When you have intermittent circuit fault, you should record longer time base, let's say 10 sec per screen, sampling rate can be low 500kb/s is totally enough.
Then connect (back probe) each wire of that affected sensor with separate scope channel.
Ideally at ecu socket if its possible, otherwise at any reachable point.
(I think your connection is incorrect when seeing your screenshot)
Let the engine run, accelerate few times and when you get the dtc, stop and save the .psdata file.
You should see the problem then, or post the file here.
Second test would be trying to play with wire harness, connectors etc. while engine running. Monitor the waveform and hoping to identify the bad connection point, the signal changes when you move wires on affected area. If its caused by poor connection.
BTW the coil spikes are normal, it depends where you connect scope earth or if any your probe lead is picking up interference from nearby coil.
Regards,
Roman
Please take my comment as generic only, I don't touch US or Japanese cars which are using inductive sensors, but some our European cars have them also.
So here is my comment, hope it helps or give you new ideas.
When you have intermittent circuit fault, you should record longer time base, let's say 10 sec per screen, sampling rate can be low 500kb/s is totally enough.
Then connect (back probe) each wire of that affected sensor with separate scope channel.
Ideally at ecu socket if its possible, otherwise at any reachable point.
(I think your connection is incorrect when seeing your screenshot)
Let the engine run, accelerate few times and when you get the dtc, stop and save the .psdata file.
You should see the problem then, or post the file here.
Second test would be trying to play with wire harness, connectors etc. while engine running. Monitor the waveform and hoping to identify the bad connection point, the signal changes when you move wires on affected area. If its caused by poor connection.
BTW the coil spikes are normal, it depends where you connect scope earth or if any your probe lead is picking up interference from nearby coil.
Regards,
Roman
Re: Ford Mustang 2015 5.0 TiVCT V8 - P0390 & P0394 - Camshaft position sensor B circuit intermittent (bank 2)
Thanks Roman for the info!
It seems I rushed into conclusions with the ignition spikes taking them as the root cause of the issue.
I will try the settings you advised.
I did probe at the ECU connector, but I ran the leads near the engine block.
I grounded all the 3 leads at the same spot on the chassis.
I will be more through in my next attempt and follow your advice.
Questions
1. Are the original Pico scope leads shielded?
2. General - is it OK to run a car with coil-on-plug setup without ignition transformer capacitor? Lets say just for testing purposes to see how much noise changes.
Thanks again! Will get back to you once I have done another round of testing.
It seems I rushed into conclusions with the ignition spikes taking them as the root cause of the issue.
I will try the settings you advised.
I did probe at the ECU connector, but I ran the leads near the engine block.
I grounded all the 3 leads at the same spot on the chassis.
I will be more through in my next attempt and follow your advice.
Questions
1. Are the original Pico scope leads shielded?
2. General - is it OK to run a car with coil-on-plug setup without ignition transformer capacitor? Lets say just for testing purposes to see how much noise changes.
Thanks again! Will get back to you once I have done another round of testing.
Re: Ford Mustang 2015 5.0 TiVCT V8 - P0390 & P0394 - Camshaft position sensor B circuit intermittent (bank 2)
Had another go.
What I did
1. All signals CPP and CKP from ECU(PCM) connector.
2. All grounds from ECU(PCM) connector.
3. Moved leads from the side, not over the engine block.
What I observed
1. No spark noise.
2. Right after start, the ECU(PCM) sets "P0390 - Camshaft Position Sensor B Circuit (Bank 2)".
3. After running a few seconds ECU(PCM) sets "P0394 - Camshaft Position Sensor B Circuit Intermittent (Bank 2)"
4. No dropouts, graphs look fine for all the sensors.
5. I do see some minute spikes on both CKP-s at times, but no dropouts. Not sure if such small spikes would set a DTC.
6. I see a new kind of noise - deltaV=200mV, with 3 x ~60ms bursts every 400ms. Which is interesting but not sure (see noise.png)
7. The suspected bad has maxV about ~500mV higher than a known good. Not sure if that has anything to do with setting the code.
8. I have swapped the sensors between banks, the code still indicates the same bank, which should mean it's not a bad sensor.
In conclusion, there are some oddities, but I am not sure which, if any, would set the DTC.
Attached the Picoscope recording in case anyone is interested in having a look.
Thanks to all!
What I did
1. All signals CPP and CKP from ECU(PCM) connector.
2. All grounds from ECU(PCM) connector.
3. Moved leads from the side, not over the engine block.
What I observed
1. No spark noise.
2. Right after start, the ECU(PCM) sets "P0390 - Camshaft Position Sensor B Circuit (Bank 2)".
3. After running a few seconds ECU(PCM) sets "P0394 - Camshaft Position Sensor B Circuit Intermittent (Bank 2)"
4. No dropouts, graphs look fine for all the sensors.
5. I do see some minute spikes on both CKP-s at times, but no dropouts. Not sure if such small spikes would set a DTC.
6. I see a new kind of noise - deltaV=200mV, with 3 x ~60ms bursts every 400ms. Which is interesting but not sure (see noise.png)
7. The suspected bad has maxV about ~500mV higher than a known good. Not sure if that has anything to do with setting the code.
8. I have swapped the sensors between banks, the code still indicates the same bank, which should mean it's not a bad sensor.
In conclusion, there are some oddities, but I am not sure which, if any, would set the DTC.
Attached the Picoscope recording in case anyone is interested in having a look.
Thanks to all!
- Attachments
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- Ford_Mustang_2015_Petrol_20231023-0001_CPP2_DTC_P0394_while_running_a_bit.psdata
- (3.03 MiB) Downloaded 80 times