Starter relay circuit error... weird key behaviour

[pangy101]

Hi all,

After much headscratching and Googling I just can't get to the bottom of this - does anyone know what might be causing the following please?

My 2013 Passat B7 has been having intermittent start issues to the point it has now become a complete non-starter. The code reader came out as saying "P308800 - Starter relay Electrical error in circuit". After quite a bit of diagnosing, I've tried replacing both starter relays, and have eliminated the relays and the starter motor as the issue. If I short-circuit starter relay 1 then the car starts fine (but still displays weird behaviour - see below). 12V is being supplied to the starter relay 1 coil, and also to the Normally Open starter solenoid wire. It's as if the ECU isn't commanding it to start.

The other weird behaviour which I don't know if is the cause, or a consequence is that the push-key seems to be allowing a start when you turn the ignition on, without pushing it in fully to start. For example if you push the key to turn the ignition on (not fully into the start position), it flashes "Press clutch to start", and if the relay has been bypassed then this is when it starts.

Ideas so far - ignition switch (local garage tried replacing this, but they were rushed so not sure they gave it a good go), BCM?, ECU?, starter relay 1 connection to ECU (but why the strange key behaviour)? There's a screenshot below of the OBDEleven code reader output, and also a screenshot of the 'live data' of the starter inhibition conditions. I don't have a decode for the starter inhibition conditions so haven't a clue what it actually means.

(FYI the P253500 code only appears if the key has been left in the ignition without starting for a few minutes). The Exhaust Gas error might just be that I've been playing around with the MAF on and off while diagnosing this issue).

Date: 2024-01-30 13:27

    VIN: WVWZZZ3CZDE051229
    Car: Volkswagen Passat
    Year: 2013
    Body type: Variant
    Engine: CAYC
    Mileage: 398710 KM

---------------------------------------------------------------
01 Engine

    System description: 1,6l R4 CR td
    Software number: 03L906023FS
    Software version: 9626
    Hardware number: 03L907425C
    Hardware version: H43
    Serial number: 00000000000000
    ODX name: EV_ECM16TDI02103L906023FS
    ODX version: 003008
    Long coding: 00194014030501080000

    Trouble codes: 
        P040200 - Exhaust Gas Recirc.Flow Excessive Detected
            static
                Mileage: 398713 km
                Priority: 2
                Malfunction frequency counter: 1
                Unlearning counter: 255
                Engine speed: 779.50 1/min
                Normed load value: 32.2 %
                Vehicle speed: 0 km/h
                Coolant temperature: 45 °C
                Intake air temperature: 23 °C
                Ambient air pressure: 1020 mbar
                Voltage terminal 30: 14.908 V
                Dynamic environmental data: 2096282037279F29D1049A20A7000020BA7AB6202930CE202A30CE2002061A
        P308800 - Starter relay Electrical error in circuit
            static
                Mileage: 398713 km
                Priority: 2
                Malfunction frequency counter: 1
                Unlearning counter: 255
                Engine speed: 0.00 1/min
                Normed load value: 0.0 %
                Vehicle speed: 0 km/h
                Coolant temperature: 41 °C
                Intake air temperature: 22 °C
                Ambient air pressure: 1020 mbar
                Voltage terminal 30: 12.536 V
                Dynamic environmental data: 209628F40C0000F40D002A076F20D6023E0A5B
        P253500 - Ignition Switch Run/ Start Position Curciut High
            static
                Mileage: 398713 km
                Priority: 2
                Malfunction frequency counter: 1
                Unlearning counter: 255
                Engine speed: 0.00 1/min
                Normed load value: 0.0 %
                Vehicle speed: 0 km/h
                Coolant temperature: 40 °C
                Intake air temperature: 22 °C
                Ambient air pressure: 1020 mbar
                Voltage terminal 30: 12.424 V
                Dynamic environmental data: 209628F40C0000F40D002A076E20D6023E0A593F8300


---------------------------------------------------------------
03 Brakes

    System description: J104   C2 450M V468
    Software number: 3AA614109AF
    Software version: 0024
    Hardware number: 3AA614109AF
    Hardware version: K03
    Serial number: 00000006145874
    Coding: 0002983

    Trouble codes: 
        No trouble codes found

---------------------------------------------------------------
04 Steering Angle Sensor


    Trouble codes: 
        No trouble codes found

---------------------------------------------------------------
08 Air Conditioning

    System description: AC Manuell
    Software number: 7N0907426BG
    Software version: 0505
    Hardware number: 7N0907426BG
    Hardware version: H20
    ODX name: EV_ACManueBHBVW36X
    ODX version: A01010
    Long coding: 0010004003

    Trouble codes: 
        No trouble codes found

---------------------------------------------------------------
09 Central Electrics

    System description: BCM PQ47 M
    Software number: 3AA937087F
    Software version: 0465
    Hardware number: 3AA937087F
    Hardware version: 421
    Long coding: 0008000000000000009800801000006403010088424D81606480C7200041

    Subsystems: 
        System description: Wischer 22081
        Software number: 3AC955119  
        Software version: 0612
        Hardware version: 26 
        Long coding: 00B795

    Trouble codes: 
        No trouble codes found

---------------------------------------------------------------
15 Airbag

    System description: J234__108 VW10 HI
    Software number: 5N0959655AA
    Software version: 2118
    Hardware number: 5N0959655AA
    Hardware version: 003
    Serial number: 003L7PJ1PWHL
    Coding: 0012344

    Trouble codes: 
        No trouble codes found

---------------------------------------------------------------
16 Steering Column

    System description: LENKS.MODUL
    Software number: 3C9953501BF
    Software version: 0140
    Hardware number: 5K0953569S
    Hardware version: 014
    Serial number: 20120821300106
    ODX name: EV_VW360SteerWheelUDS
    ODX version: A03004
    Long coding: 1182250000

    Subsystems: 
        System description: E221__MFL-TK6
        Software number: 3C8959537D 
        Software version: 0022
        Hardware version: H07
        Long coding: E20000

    Trouble codes: 
        No trouble codes found

---------------------------------------------------------------
17 Dashboard

    System description: KOMBI
    Software number: 3AA920970J
    Software version: 0705
    Hardware number: 3AA920970J
    Hardware version: H05
    Serial number: 00000000000000
    ODX name: EV_Kombi_UDS_VDD_RM09
    ODX version: A04716
    Long coding: 461F00

    Trouble codes: 
        No trouble codes found

---------------------------------------------------------------
19 Gateway

    System description: J533  Gateway
    Software number: 7N0907530T
    Software version: 1632
    Hardware number: 7N0907530K
    Hardware version: H40
    Serial number: 140812F2001967
    Long coding: 462007

    Trouble codes: 
        No trouble codes found

---------------------------------------------------------------
25 Immobilizer

    System description: IMMO         045
    Software number: 3AA959433
    Software version: 0400
    Hardware number: 3AA959433
    Hardware version: 008
    Serial number: VWZCZ000000000

    Subsystems: 
        System description: ELV          029
        Software number: 3C0905861J
        Software version: 0380

    Trouble codes: 
        No trouble codes found

---------------------------------------------------------------
2E Media Player 3

    System description: SG EXT.PLAYER
    Software number: 5N0035342F
    Software version: 0546
    Hardware number: 5N0035342F
    Hardware version: H18
    Serial number: 7663344392
    Long coding: 010100

    Trouble codes: 
        No trouble codes found

---------------------------------------------------------------
42 Driver Door

    System description: TUER-SG FT
    Software number: 3AA959701
    Software version: 0534
    Hardware number: 3C0959793B
    Hardware version: 002
    Serial number: 0005268577
    ODX name: EV_TSGFPQ35BRFVW46X
    ODX version: A04001
    Long coding: 0202B5

    Subsystems: 
        System description: J389__TSG-HR 
        Software number: 3AA959704A 
        Software version: 0503
        Hardware version: 004
        Serial number: 00000003100142      
        Long coding: 010290

    Trouble codes: 
        No trouble codes found

---------------------------------------------------------------
44 Steering Assistance

    System description: EPS_ZFLS Kl. 194
    Software number: 1K0909144P
    Software version: 3305

    Trouble codes: 
        03803 - Steering angle sensor for power-assisted steering
            static
                Priority:  2
                Frequency counter:  1
                Driving cycle: 255
                Mileage: 398713 km


---------------------------------------------------------------
46 Comfort System

    System description: KSG PQ47 ELV 045
    Software number: 3AA959433
    Software version: 0634
    Hardware number: 3AA959433
    Hardware version: 008
    Serial number: VWZCZ000000000
    Long coding: 019102005A830E76340494157C085FCE105801

    Subsystems: 
        System description: LIN BACKUP HORN H05
        Software number: 1K0951605C
        Software version: 1501

        System description: Neigungssensor  004
        Software number: 3C0951171C
        Software version: 0611

        System description: Innenraumueberw.004
        Software number: 3C0951171C
        Software version: 0611

    Trouble codes: 
        No trouble codes found

---------------------------------------------------------------
4F Central Electrics 2

    System description: EZE_2
    Software number: 7N0907532
    Software version: 1632
    Hardware number: 7N0907530K
    Hardware version: H40
    Serial number: 140812F2001967
    Long coding: 00000008

    Subsystems: 
        System description: Analoguhr    
        Software number: 3AA919204A 
        Software version: 0004
        Hardware version: 004

    Trouble codes: 
        No trouble codes found

---------------------------------------------------------------
52 Passenger Door

    System description: TUER-SG BT
    Software number: 3AA959702
    Software version: 0534
    Hardware number: 3C0959792B
    Hardware version: 002
    Serial number: 0005264885
    ODX name: EV_TSGBPQ35BRFVW46X
    ODX version: A04001
    Long coding: 0202B4

    Subsystems: 
        System description: J388__TSG-HL 
        Software number: 3AA959703A 
        Software version: 0503
        Hardware version: 004
        Serial number: 00000003100831      
        Long coding: 010290

    Trouble codes: 
        No trouble codes found

---------------------------------------------------------------
53 Parking Brake

    System description: J540 EPB4  VW-86594
    Software number: 3AA907801H
    Software version: 0010
    Hardware number: 3AA907801H
    Serial number: 00000000415120
    Coding: 0022167

    Trouble codes: 
        No trouble codes found

---------------------------------------------------------------
56 Radio

    System description: Radio RCD310
    Software number: 1K0035186AQ
    Software version: 0119
    Hardware number: 1K0035186AQ
    Hardware version: 004
    Serial number: VWZ1Z2M9669314
    Long coding: 01000400040011

    Trouble codes: 
        No trouble codes found

---------------------------------------------------------------
61 Battery Regulation

    System description: Batt.regelung
    Software number: 7N0907534
    Software version: 1632
    Hardware number: 7N0907530K
    Hardware version: H40
    Serial number: 140812F2001967
    Long coding: 030F1859

    Subsystems: 
        System description: J367-BDM     
        Software number: 1K0915181H 
        Software version: 0180
        Hardware version: H07
        Serial number: 00000000008900064955

    Trouble codes: 
        No trouble codes found

---------------------------------------------------------------
62 Rear Left Door


    Trouble codes: 
        No trouble codes found

---------------------------------------------------------------
72 Rear Right Door


    Trouble codes: 
        No trouble codes found

---------------------------------------------------------------
77 Telephone

    System description: TELEFON
    Software number: 7P6035730J
    Software version: 3200
    Hardware number: 7P6035730J
    Hardware version: H15
    Serial number: 00007663308760
    ODX name: EV_UHVNA
    ODX version: 002720
    Long coding: 0A01000000010101

    Trouble codes: 
        No trouble codes found

Screenshot_20240130_135058_OBDeleven.jpgScreenshot_20240130_135052_OBDeleven.jpg

[Crasher]

I would start, sorry, begin by replacing the two starter relays 643 (now 645) 4H0 951 253 A and 489 6Q0 951 253 in the supplementary relay holder at positions 1 and 6 respectively.

[pangy101]

Thanks Crasher, tried that earlier - still doesn't help but I can tell that the smaller 489 clicks correctly but it's the 643 that doesn't click at all. 12v is supplied correctly to the 643 solenoid.

If I bypass relay 643 with a small wire then it starts correctly... but the weird key behaviour still happens.

[Crasher]

New switch unit next although the data I can see at home is confusing.

[pangy101]

Sorry do you mean ignition switch? If I get a matching used part off ebay with a linked key then is this just plug and play or does it still need to be coded in? Cheers!

[Crasher]

It isn't a coded part or vehicle specific, part number 3C0 905 843 AE and £93.60 retail inc VAT. Used electronic parts are a mugs game. However, sometimes the central electrics unit is the problem and they get seriously complicated to replace as they are a Vehicle Intelligent Part, special order from Germany in many cases, have to be paid for up front (£526.80), cannot be canceled or returned for ANY reason EVEN if found to be faulty straight out of the box. In that situation you have to engage in the fun of a TPS warranty claim, solving the Israel Gaza crisis is less complex and more achievable! Also with the type 36 the central electrics has a trick up its sleeve. It comes locked and needs coding, if you try and do this with anything other than ODIS it has the potential to screw up the coding on nearly all the cars controllers and in one case recoded the ABS pump for left hand drive and locked the ECU making the car pull to the left and the ABS light stuck on. The only way to get around it was a new ABS unit... try explaining that one to a customer!

[pangy101]

Thanks for the detailed reply! Crikey that CCM is expennnsive... almost not worth it for a 250k mile car! Would hate to scrap it just because of an electrical gremlin though... what a waste!

Another gremlin appeared last week, in that whenever I unlock the car using the keyfob (or press the 'unlock all doors' button inside) the boot motor operates and pops the boot open slightly. The switch on the tailgate doesn't operate, however OBDEleven shows that the car knows when the switch is operated, but it just doesn't open the boot!! No faults from CCM but do you think it's safe to assume it's combined with the ignition key issue and it might be corrosion on the module?

Cheers!

[Crasher]

I am in the process of spending £100K on a 1995 Audi 80...

[pangy101]

£100k, that's dedication!!

I've had another couple of issues appear with the electrics - the boot unlock doesn't work, and the fuel tank filler lock is throwing up an error. There's defo no prob in the wiring as I checked continuity to the Central Convenience Unit, so if this module's dodgy then could it also be the cause of the ignition problem?

If this error is present "P253500 - Ignition Switch Run/ Start Position Curciut High" would the ECU prevent sending a terminal 15 signal to activate the starter relays?

Sorry, so many questions, I'm so confused - hoping it's not one of the modules!