ECU terminal 30 measuring point

[scoper]

Diesel 1.6 Audi A3 that very intermittently cuts out when driving, Code set was

7078 - Supply Voltage for Fuel Injector Group A
P2147 00 [104] - Short to Ground
[Fuel Injector Group "A" Supply Voltage Circuit Low]
............
Engine RPM: 1774.50 /min
Voltage terminal 30: 12.085 V
............

Did the usual checks, 500v insulation test on the injectors, wiggled the injector wires, tapped the ecu etc. Noted that the Terminal 30 voltage at time of fault was 12.08v but the engine was apparently still at 1700 RPM -
Is the ECU reporting voltage downstream of the Main relay or from it's permanent battery supply or is it on the network ? If that's relay output then that gives me direction.
Unfortunately that was the only code set so no voltages to compare

Obligatory scan

Thursday,01,December,2022,10:25:06:34176
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 10 x64
VCDS Version: 22.10.0.1 (x64)  HEX-V2 CB: 0.4623.4
Data version: 20221026 DS344.0
www.Ross-Tech.com

Dealer/Shop Name:

VIN: TRUZZZ8P9A1007968   License Plate:


Chassis Type: 8P-AU35 (1K0)
Scan: 01 03 08 09 10 15 16 17 19 25 26 42 44 46 47 52 56 61 62 72
     

VIN: TRUZZZ8P9A1007968   Mileage: 149730km-93037miles

01-Engine -- Status: Malfunction 0010
03-ABS Brakes -- Status: OK 0000
04-Steering Angle -- Status: OK 0000
08-Auto HVAC -- Status: OK 0000
09-Cent. Elect. -- Status: OK 0000
10-Park/Steer Assist -- Status: OK 0000
15-Airbags -- Status: OK 0000
16-Steering wheel -- Status: OK 0000
17-Instruments -- Status: OK 0000
19-CAN Gateway -- Status: OK 0000
25-Immobilizer -- Status: OK 0000
26-Auto Roof -- Status: OK 0000
42-Door Elect, Driver -- Status: OK 0000
44-Steering Assist -- Status: OK 0000
46-Central Conv. -- Status: OK 0000
47-Sound System -- Status: OK 0000
52-Door Elect, Pass. -- Status: OK 0000
56-Radio -- Status: OK 0000
61-Battery Regul. -- Status: OK 0000
62-Door, Rear Left -- Status: OK 0000
72-Door, Rear Right -- Status: OK 0000
-------------------------------------------------------------------------------
Address 01: Engine (J623-CAYC)       Labels:. 03L-906-023-CAY.clb
   Part No SW: 03L 906 023 M    HW: 03L 906 023 L
   Component: R4 1.6l TDI   H23 9979
   Revision: --H23---    Serial number: AUX7Z0J1FNH01T CVN: 4F2DF892
   Coding: 00114034032501080000
   Shop #: WSC 00497 210 88415
   ASAM Dataset: EV_ECM16TDI02103L906023M 003017
   ROD: EV_ECM16TDI02103L906023JK_003.rod
   VCID: 30391D723AAB0B8B5B2-8064
   VINID: 92296AAAA220251040007246203ADFFB01

1 Fault Found:
7078 - Supply Voltage for Fuel Injector Group A
          P2147 00 [104] - Short to Ground
          [Fuel Injector Group "A" Supply Voltage Circuit Low]
          Intermittent - Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 14
                    Mileage: 149728 km
                    Date: 2022.11.22
                    Time: 22:53:36

                    Engine RPM: 1774.50 /min
                    Normed load value: 60.0 %
                    Vehicle speed: 29 km/h
                    Coolant temperature: 49 °C
                    Intake air temperature: 16 °C
                    Ambient air pressure: 970 mbar
                    Voltage terminal 30: 12.085 V
                    Unlearning counter according OBD: 40
                    Error information regarding selected piezo output stage-LF_STATE_PPS_SPI[0]: 2
                    Injection valve 1: voltage-V_INJ_MAIN[0]: 127.21 V
                    Injection valve 2: voltage-V_INJ_MAIN[1]: 124.06 V
                    Supply voltage of analog output 1-VCC_1: 5.03 V
                    Supply voltage of analog output 2-VCC_2: 5.00 V
                    Injection valve 3: voltage-V_INJ_MAIN[2]: 126.48 V
                    Injection valve 4: voltage-V_INJ_MAIN[3]: 126.25 V

Readiness: 0 1 0 0 0

-------------------------------------------------------------------------------
Address 03: ABS Brakes (J104)       Labels:. 1K0-907-379-60EC1F.clb
   Part No SW: 1K0 907 379 AJ    HW: 1K0 907 379 AJ
   Component: ESP MK60EC1   H30 0107
   Revision: 00H30001
   Coding: 1342201249220001C81404EA92210091380800
   Shop #: WSC 55729 003 1048576
   VCID: 7AADFF5AACD701DBA56-802E

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC        Labels: 8P0-820-047.clb
   Part No SW: 8P0 820 047 D    HW: 8P0 820 047 D
   Component: J255  Klima Man H08 0060
   Revision: 00H08004    Serial number: 00000000000000
   Shop #: WSC 00000 000 00000
   VCID: 313F18763D21028354C-8064

No fault code found.

-------------------------------------------------------------------------------
Address 09: Cent. Elect. (J519)       Labels:. 8P0-907-063.clb
   Part No SW: 8P0 907 063 A    HW: 8P0 907 063 A
   Component: BCM PQ35  M   105 0575
   Revision: 00105 AK
   Coding: 0E000A0FB205F140207060E00100004C53725CAA0020C122E4008F000055
   Shop #: WSC 01236 758 00200
   VCID: 323D177A3427399B2D6-8066

   Subsystem 1 - Part No SW: 8P2 955 119 F    HW: 8P2 955 119 F  Labels: 1KX-955-119.CLB
   Component: Wischer AU350  H10 0040
   Coding: 00DD13

   Subsystem 2 - Part No SW: 8K0 910 557     HW: 8K0 955 559 A  Labels: 8K0-955-559.CLB
   Component: REGENLICHTSEN  H04 0003
   Coding: 024C2D

   Subsystem 3 - Part No: 8P7 951 177
   Component: DWA-Sensor H0  H03 0040

   Subsystem 4 - Part No: 1K0 951 605 C
   Component: LIN BACKUP HO  H05 1501

No fault code found.

-------------------------------------------------------------------------------
Address 10: Park/Steer Assist (J446)       Labels:. 8P0-919-475-7X1.clb
   Part No SW: 8P0 919 475 G    HW: 8P0 919 475
   Component: PARKHILFE 4K  H06 0120
   Revision: 11001001    Serial number: 93641004402386
   Coding: 000001
   Shop #: WSC 01236 758 00200
   VCID: 42DD47BA8487891BBD6-8016

No fault code found.

-------------------------------------------------------------------------------
Address 15: Airbags        Labels: 8P7-959-655.clb
   Part No SW: 8P7 959 655     HW: 8P7 959 655
   Component: SR Airbag 9.43  H01 0020
   Revision: 93H01002    Serial number: 003BS000WTGX
   Coding: 0021330
   Shop #: WSC 01236 785 00200
   VCID: 06559BAAE42F753BD1E-8052

   Subsystem 1 - Serial number: 6332DRB409AB880C+

   Subsystem 2 - Serial number: 6342DRB409AB0F33Z

   Subsystem 3 - Serial number: 63747RB40557BDC1.

   Subsystem 4 - Serial number: 63847RB40557BD2D/

No fault code found.

-------------------------------------------------------------------------------
Address 16: Steering wheel        Labels: 8P0-953-549.lbl
   Part No SW: 8P0 953 549 K    HW: 8P0 953 549 K
   Component: J0527           H37 0070
   Coding: 0002041
   Shop #: WSC 01236 785 00200
   VCID: 46D55BAAA4AFB53B91E-8012

   Subsystem 1 - Part No: XXXXXXXXXXX
   Component: E0221           H02 0100

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments        Labels: 8P0-920-xxx-17-MY8.clb
   Part No SW: 8P0 920 982 J    HW: 8P0 920 982 J
   Component: KOMBIINSTR. VDO H03 0990
   Revision: D0H03005    Serial number: 2241J005019554
   Coding: 0004428
   Shop #: WSC 12345 123 12345
   VCID: 40D94DB2868B9B0BAB2-8014

No fault code found.

-------------------------------------------------------------------------------
Address 19: CAN Gateway        Labels:. 1K0-907-530-V4.clb
   Part No SW: 1K0 907 530 AF    HW: 1K0 907 951
   Component: J533  Gateway   H17 0233
   Revision:   H17       Serial number: 1521J102040BA1
   Coding: E9A07F26100202049101
   Shop #: WSC 01236 785 00200
   VCID: 6B83CA1EDF8DA8532E0-803E

No fault code found.

-------------------------------------------------------------------------------
Address 25: Immobilizer        Labels: 1K0-920-xxx-25.clb
   Part No SW: 8P0 920 982 J    HW: 8P0 920 982 J
   Component: KOMBIINSTR. VDO H03 0990
   Revision: D0H03005    Serial number: AUX7Z0J1FNH01T
   Shop #: WSC 00000 000 00000
   VCID: 40D94DB2868B9B0BAB2-8014

No fault code found.

-------------------------------------------------------------------------------
Address 26: Auto Roof        Labels: Redir Fail!
   Part No: 8P7 959 255 B
   Component: VSG AUDI A3     H14 0130
   Shop #: WSC 00000 000 00000
   VCID: 44D141A29293872B8FA-8010

No fault code found.

-------------------------------------------------------------------------------
Address 42: Door Elect, Driver        Labels: None
   Part No SW: 8P7 959 801 D    HW: 8P7 959 801 D
   Component: Tuer-SG         H04 0100
   Coding: 0131764
   Shop #: WSC 01236 785 00200
   VCID: 43D342BE979D8013B60-8016

No fault code found.

-------------------------------------------------------------------------------
Address 44: Steering Assist        Labels: 1K0-909-14x-GEN3.clb
   Part No: 1K0 909 144 J
   Component: EPS_ZFLS Kl. 232    3001
   Revision: 00H17000
   Shop #: WSC 01236 785 00200
   VCID: 313F18763D21028354C-8064

No fault code found.

-------------------------------------------------------------------------------
Address 47: Sound System        Labels: 8Px-035-382.lbl
   Part No SW: 8P7 035 382 C    HW: 8P7 035 382 C
   Component: AB2 SUBWOOFERBOXH04 0160
   Revision: 00003       Serial number: 92159949691792
   Shop #: WSC 00000 000 00000
   VCID: 372B266ED345DCB31A8-8062

No fault code found.

-------------------------------------------------------------------------------
Address 52: Door Elect, Pass.        Labels:. 1K0-959-702-MIN3.clb
   Part No SW: 8P7 959 802 F    HW: 8P7 959 802 F
   Component: Tuer-SG         H04 0103
   Coding: 0131764
   Shop #: WSC 01236 785 00200
   VCID: 46D55BAAA4AFB53B91E-8012

No fault code found.

-------------------------------------------------------------------------------
Address 56: Radio        Labels: 8J0-035-1xx-56.clb
   Part No SW: 8P0 035 186 S    HW: 8P0 035 186 S
   Component: R Concert2+     H03 0280
   Revision: 00H03000    Serial number: AUZ1Z3K6011420
   Coding: 0330211
   Shop #: WSC 01236 785 00200
   VCID: 42DD47BA8887891BBD6-8016

No fault code found.

-------------------------------------------------------------------------------
Address 61: Battery Regul. (J840)       Labels:. 1K0-907-534.clb
   Part No SW: 1K0 907 534     HW: 1K0 907 951
   Component: Batt.regelung H17 0233
   Revision: --------    Serial number: 1521J102040BA1
   Coding: 0303085A
   Shop #: WSC 01236 758 00200
   VCID: 6889B512C27B834B432-803C

   Subsystem 1 - Part No SW: 1K0 915 181 C    HW: 1K0 915 181 A
   Component: J367-BDM  H07 0125
   Serial number: 00000000002791011196

No fault code found.

-------------------------------------------------------------------------------
Address 62: Door, Rear Left        Labels:. 1K0-959-703-GEN3.clb
   Part No SW: 8P7 959 811 B    HW: 8P7 959 811 B
   Component: Tuer-SG         H01 0050
   Coding: 0131216
   Shop #: WSC 01236 785 1012552
   VCID: 42DD47BA8887891BBD6-8016

No fault code found.

-------------------------------------------------------------------------------
Address 72: Door, Rear Right        Labels:. 1K0-959-704-GEN3.clb
   Part No SW: 8P7 959 812 B    HW: 8P7 959 812 B
   Component: Tuer-SG         H01 0050
   Coding: 0131216
   Shop #: WSC 01236 785 1012552
   VCID: 43D342BE979D8013B60-8016

No fault code found.

End----------(Elapsed Time: 01:24, VBatt start/end: 12.3V/12.1V)-----------

 

[siLc]

ECU is probably reporting the voltage on it's +12V connector pins. ECU is fed by direct battery power via fuse SB13.

The main relay J317 is not directly providing power to the injectors, the ECU itself is. If J317 was inop, you wouldn't have working glowplugs and other things, also a fault code present to that effect.

 

[DrPeter]

Hello,

Is the ECU reporting voltage downstream of the Main relay or from it's permanent battery supply or is it on the network ? If that's relay output then that gives me direction.

The ECM fault code P2147- Fuel Injector Group "A" Supply Voltage Circuit Low sets when there is a concern with the internal power supply from the ECM to one or more Injector or there wiring. I believe this is accomplished when the ECM has detected excessive current draw on the injector, (greater than 12.0 amps?)

If the vehicle starts and runs, the condition that sets the fault code is not present.

You can check each injector's resistance, they should be 50 ~ 700 kOhm. Replace any suspect injectors.

If that is okay, then you will need to check each of the wires, connectors for the injectors to and from the ECM. An overlay harness maybe needed. Worst case, it could be an internal ECM failure?


We recommend to use the Official Factory Repair Information when attempting repairs and diagnostics on these vehicle.

Hope this helps,

drpeter

 

[scoper]

ECU is probably reporting the voltage on it's +12V connector pins. ECU is fed by direct battery power via fuse SB13.

The main relay J317 is not directly providing power to the injectors, the ECU itself is. If J317 was inop, you wouldn't have working glowplugs and other things, also a fault code present to that effect.

Thanks, - VW data for the this car - 1.6 Tdi CAYC shows SB13 as down stream from T30 relay, its a 30A fuse, direct power is on SB10 a 5A fuse. Whilst the ECU supplies power to the injectors the injector capacitor charge is coming from that 30A feed I assume. Is there a Group B ? Usually piezos are 2 per driver but group A might refer to all 4.

The ECM fault code P2147- Fuel Injector Group "A" Supply Voltage Circuit Low sets when there is a concern with the internal power supply from the ECM to one or more Injector or there wiring. I believe this is accomplished when the ECM has detected excessive current draw on the injector, (greater than 12.0 amps?)

As mentioned this is intermittent so fault not present, all injectors ohm'd out at 200k as expected, all passed an insulation test >30Mohms
On the scan it shows the same voltage on all the injectors, at time of fault. 126v.
What stood out was the voltage shown on T30 as 12.08v at time of fault set. So the question is does it measure that at the 5A direct feed or the 30A via the relay?
I can probably see going bad relay contacts or a weak coil on the 'scope, but if the ECU is reporting from the 5A direct feed then I need to be looking at why the battery (or at least that fuse!) is at 12.08A when the car is in operation.

Of course it might be an unrelated fault and it's something like a faulty CKP but this is what I have to work with. Though at the moment I have said to bring it back when it is more broken..

 

[siLc]

Thanks, - VW data for the this car - 1.6 Tdi CAYC shows SB13 as down stream from T30 relay, its a 30A fuse, direct power is on SB10 a 5A fuse. Whilst the ECU supplies power to the injectors the injector capacitor charge is coming from that 30A feed I assume. Is there a Group B ? Usually piezos are 2 per driver but group A might refer to all 4.

You're right, I misread that WD. Yes, most definetly. Probably doesn't matter how many piezos are as each injector only has two leads going to it - power and ground.

 

[scoper]

I was thinking that if Group A is 1+3 and group B is 2+4 then it will likley not be an ECU supply fault as it would have set codes for both, but if Group A means "Bank A" ie all of them on a 4cyl then it's worth chasing down that relay supply with the scope.

If I have to drag the ECU out anyway then I can insulation test the ECU to injector harness.

 

[Crasher]

I was thinking that big rectangular lump in the left corner of the engine bay

 

[scoper]

Good point - assuming you mean the battery, it's not been changed since the last fault, it tested OK and even KOEO for a while it's showing 12.1v Ign on at the last line of the scan. Also I would expect a bunch of low voltage codes to have set when I cranked it...
Annoying there is not another module with a fault report at the same time that would give me another voltage reading. AGM battery as it is S/S too.

 

[DrPeter]

Hello again,

So the question is does it measure that at the 5A direct feed or the 30A via the relay?

If the freeze frame data shows "Voltage terminal 30: 12.085 V", this is an internal voltage at the ECM, it could becoming from either and/or both(averaging?) the D104 / D108 Terminal 30 power connections.

I do not see the [12.085 V] battery voltage the cause of the P2147 fault code, I say this because, if my information is correct and the P2147 fault code sets due to an excessive amperage draw on the injector circuit(s), not low voltage.

Silly question, have you checked the Basics? Battery voltage, Alternator Output, etc...??
Also have a look at the Advanced Measuring Values with VCDS, with the engine running and/or while on a test drive when some one lese is driving, be Safe!

If your alone, you can 'Data-Log' these values (below) and post them here if you can get the vehicle to stall and set the P2147 fault code again.

I suggest to use the following Measuring Values:

[*IDE00019*] - Voltage terminal 30
[*IDE00021*] - Engine RPM

[*IDE00437*] - Injector valve 1: capacity - CAPA_INJ_MAIN[0]
[*IDE00438*] - Injector valve 2: capacity - CAPA_INJ_MAIN[1]
[*IDE00439*] - Injector valve 3: capacity - CAPA_INJ_MAIN[2]
[*IDE00440*] - Injector valve 4: capacity - CAPA_INJ_MAIN[3]

[*IDE03893*] - Injection valve 1: voltage - V_INJ_MAIN[0]
[*IDE03894*] - Injection valve 2: voltage - V_INJ_MAIN[1]
[*IDE03895*] - Injection valve 3: voltage - V_INJ_MAIN[2]
[*IDE03896*] - Injection valve 4: voltage - V_INJ_MAIN[3]


Let us know what you see find,


drpeter

 

[Crasher]

Good point - assuming you mean the battery

Yes, it is getting to that time of night when one should observe but not comment