AGR Problem 2.0 TDI (CFFB) - Troubleshooting

Hello,

"I'm having problems with the exhaust gas recirculation system in my Golf. It started with very occasional white smoke, maybe once every 1,000 km. There was also a slight coolant leak. After the check engine light came on, I was able to read the engine control unit and got the following error code:"

Vehicle type: 1K (7N0)
Scan: 01 03 08 09 10 15 16 17 19 25 2E 42 44 46 47 52 55 56

Vehicle Identification Number: WVWZZZ1KZBW211419
Mileage: 241,830 km

01-Motor electronics -- Status: Error 0010.
03-Brake electronics -- Status: OK 0000
04-Steering angle sensor -- Status: OK 0000
08-Climate control/heating unit -- Status: OK 0000
09-Central Electrical System -- Status: OK.
Parking Assist 10 -- Status: OK 0000
15-Airbag -- Status: OK 0000
16-Wheel steering electronics -- Status: OK 0000
17-Terminal block insert -- Status: OK 0000
19-Diagnosis interface -- Status: OK 0000.
Immobilizer system -- Status: OK 0000
2E-Media Player 3 -- Status: OK 0000
42-Door Electric Driver -- Status: OK 0000
44-Steering Assist -- Status: OK 0000
46-Comfort System -- Status: OK 0000
47-Sound System -- Status: OK 0000
52-door electric passenger door - Status: OK 0000.
55-Beam adjustment. -- Status: OK 0000.
56-Radio -- Status: OK 0000

"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Ein leichter Wind weht durch die Bäume, und die Blätter rascheln leise. Es ist ein wunderschöner Tag, um draußen zu sein."
Address 01: Engine Control Module (J623-CFFB)
Label file: DRV\03L-906-018-CFF.clb
Part number SW: 03L 906 018, HW: 03L 907 309 R.
Component: R4 2.0L EDC H23 7453
Revision: 42H23--- Serial number: 00000000000000
Encoding: 00190012042400080000
Operating number: WSC 01357 011 00200
ASAM Dataset: EV_ECM20TDI01103L906018 003010
ROD: EV_ECM20TDI01103L906018_VW36.rod
VCID: 67DBE0399EC4EA06DF-8032

"One error found:"
4871 - Valve for cooling exhaust gas recirculation.
P2425 00 [039] - Interruption.
unconfirmed - checked since last deletion.
Environmental conditions:
Error status: 00000001
Error priority: 2
Error frequency: 1.
Mileage: 241,833 km
Date: 2016.05.16
Time: 12:53:49

Readiness: 0 0 0 0 1

I have already installed two used AG (automatic gearbox) units (supposedly from vehicles that were involved in accidents), but the error message persists with both units, and the smoking has become much more frequent with both. This increase in smoking occurred immediately after the first replacement.

Can I assume that both used units, plus the old AG unit, are defective, and that the error code refers to a problem with the wiring harness?

Regards,
Thomas.

Hello Thomas,

The interruption of the electrical connection can occur in the connecting cable, the plug(s), or the actuator/valve itself.

I would start by using a multimeter to measure the resistance of the existing valves and compare the readings.

White exhaust smoke should not be present in any case; it's possible that the EGR cooler is also leaking, and coolant is entering the engine's intake manifold via the EGR system?

Best regards, Rainer.

Are there any insights into what caused it?

Because...

Quote:

Tuesday, May 9, 2017, 6:34:59:15096 VCDS version: RKS 17.1.3 is running on Windows 8.1 x64. http://shop.dieselschrauber.de Address 01: Engine Control Module Label file: DRV\03L-906-018-CFF.clb Control unit part number: 03L 906 018 AB. Hardware: 03L 906 018 AG. Part and/or version: R4 2.0l TDI H20 9979. Encoding: 00190012042401080000 Operating number: WSC 57355 001 1048576 ASAM Dataset: EV_ECM20TDI01103L906018AB 003012 (AU35) ROD: EV_ECM20TDI01103L906018AB.rod VCID: 6AF49B3A8D45111157-803E 3 error codes found: 4871 - Valve for cooling exhaust gas recirculation. P2425 00 [168] - Interruption. Warning light ON - Intermittent - Confirmed - Checked since last reset. Environmental conditions: Error status: 00000001 Error priority: 2 Error frequency: 25 Mileage: 148,232 km Date: 2017.05.09 Time: 08:40:54 Motor speed: 1415.50 rpm Normalized load value: 87.1% Vehicle speed: 83 km/h Coolant temperature: 87 °C Intake air temperature: 11 °C Atmospheric pressure: 960 millibars. Voltage at terminal 30: 14.960 V. Lost learning counter via OBD: 40. Coolant temperature at the radiator outlet: Actual value: 24.8 °C. Exhaust gas recirculation cooler bypass valve: Status bit 0: 00000001. Exhaust gas recirculation: Deactivation conditions - Bit 0: 00000000. Exhaust gas recirculation: Deactivation conditions bit 16: 00000000. Exhaust gas recirculation: Deactivation conditions - Bit 24: 00000000. Exhaust gas recirculation: Deactivation conditions bit 8: 00000111. Exhaust gas recirculation cooling function: Status bit 0: 00000000. Exhaust gas recirculation cooler pump: Target value: 93.57%. Exhaust gas recirculation temperature sensor after the cooler: Raw value: -270.6 °C. Exhaust temperature sensor 1: 467.0 °C 10085 - Actuator for transmission neutral position. P15A1 00 [096] - implausible signal. Sporadic - unconfirmed - checked since last deletion. Environmental conditions: Error status: 00000001 Error priority: 2 Error frequency: 1. Mileage: 147,220 km Date: 2017.04.23 Time: 14:35:16 Motor speed: 836.50 rpm. Normalized load value: 22.0% Vehicle speed: 0 km/h Coolant temperature: 88 °C Intake air temperature: 16 °C Atmospheric pressure: 950 millibars. Voltage at terminal 30: 14.660 V. Lost learning counter via OBD: 25. Transmission neutral position sensor: current shift angle: -14.00 ° Transmission neutral position sensor: learned shift angle: -0.40 ° Voltage from the sensor for transmission neutral position: 1890 mV. Embedded gear-bit 0: 00000000 10086 - Sensor for transmission neutral position. P15A1 00 [096] - implausible signal. Sporadic - unconfirmed - checked since last deletion. Environmental conditions: Error status: 00000001 Error priority: 2 Error frequency: 1. Mileage: 147,220 km Date: 2017.04.23 Time: 14:35:16 Motor speed: 836.50 rpm. Normalized load value: 22.0% Vehicle speed: 0 km/h Coolant temperature: 88 °C Intake air temperature: 16 °C Atmospheric pressure: 950 millibars. Voltage at terminal 30: 14.660 V. Lost learning counter via OBD: 25. Transmission neutral position sensor: current shift angle: -14.00 ° Transmission neutral position sensor: learned shift angle: -0.40 ° Voltage from the sensor for transmission neutral position: 1890 mV. Embedded gear-bit 0: 00000000 Readiness: Not Available.

The error message from the transmission neutral position sensor is also not entirely clear to me; the corresponding diagnostic measurement shows that the sensor is functioning correctly.
Coincidence, or are the cables simply placed next to each other?

A quick search for "AGR cooler CFFB" in image search reveals a block with a pneumatic switching valve, and yes, the AGR valve itself.

The valve for the cooling exhaust gas recirculation system would be the solenoid valve, which actuates the pneumatic diverter valve.

Best regards, Rainer.

The errors cleared themselves, so I suspect a cable problem... I will take a closer look at the issue during the next service, as everything is a bit cramped.

After the oil level sensor also indicated a defect, the following was discovered: cable damage caused by rodent chewing.
The solenoid valve for the EGR cooling system is located at the front of the engine, on the right-hand side above the throttle valve.

To disassemble the pins in the connector, follow these steps:
- It's best to completely disconnect the plug, as the very short cable could otherwise cause a seizure. Before doing so, make sure to remember which cable was connected to which pin on the plug.
- Remove the pink retaining clip from the connector using a flat-head screwdriver.
- Use a wire or a small Allen wrench to remove the sealing ring.
- Bend a paperclip into a U-shape and insert it from the front, outside, next to the contact pin.
- Using a wire, push the contact pin and seal backwards out of the connector housing from the center. Some forward and backward movement and fiddling was necessary for me; the paperclip had difficulty releasing the connector pin from the housing. There is also proper tool available for this, but it's questionable whether it's worth buying just for your own vehicle.
- Pry apart the metal casing at the back of the connector pin and slide the seal backwards.
- Cut off the old cable, solder the new cable in place, reinsert the seal, bend the metal casing back together, and reassemble everything.

Best regards, Rainer.