Which Fault Codes Appear When the Audi A4 B8 ABS Module Fails

The Audi A4 B8 ABS control module — supplied by Bosch and fitted from 2007 through 2012 — stores codes in both the ABS and ESP address blocks simultaneously when it begins to fail. The codes themselves do not prove the module is dead; several of them are set just as reliably by a corroded wheel speed sensor ring, a damaged wiring harness at the rear axle, or a low supply voltage at the module connector. Working through the codes in the right order is how you avoid replacing a perfectly serviceable unit.

What the ABS Module Actually Monitors on the A4 B8

The A4 B8 uses an ABS / ESP combined unit — on most variants this is a Bosch ESP 8.0 or Bosch ESP 9.0 assembly. The hydraulic unit and the control module are a single bolted assembly on the brake booster bracket in the engine bay. The module reads four wheel speed sensors over individual hardwired lines, monitors brake pressure via an internal sensor, receives yaw rate and lateral acceleration data over the CAN bus from a separate sensor cluster mounted under the centre console, and communicates with the instrument cluster and the gateway over the high-speed CAN.

That CAN dependency is important: a gateway fault or a bus interruption can cause ABS codes that have nothing to do with the ABS module itself. For comparison, see Audi A4 B8 ABS Control Module Fault Codes and Warning Lights.

Error Codes: What Appears and What It Means

The following codes are logged in address block 03 (ABS Brakes) and sometimes mirrored in address block 01 (Engine) or 19 (CAN Gateway) depending on variant and software version. All codes below are in the VAG fault code format used by VCDS / OBD-II generic tools.

• 00283 — ABS Wheel Speed Sensor Rear Left (G46): Signal Outside Tolerance — most commonly a damaged reluctor ring or corroded sensor connector, but also set by internal module ADC faults when the module hardware begins to fail.
• 00282 — ABS Wheel Speed Sensor Rear Right (G45): Signal Outside Tolerance — same interpretation as 00283; when both rear sensors log simultaneously without any physical sensor damage, suspect the module input stage.
• 00290 / 00291 — ABS Wheel Speed Sensor Front Left/Right: Implausible Signal — less common in module failure; more often caused by tone ring damage or air gap issues after wheel bearing replacement.
• 01130 — Hydraulic Pump Motor: Short to Ground — can be an internal pump failure or a wiring fault at the pump relay circuit, but is also set when the module’s internal pump driver transistor fails. This one often accompanies complete ABS/ESP deactivation.
• 01044 — Control Module Incorrectly Coded — appears after a module swap where variant coding was not completed. It does not indicate a hardware fault in the new module.
• 00668 — Supply Voltage: Too Low — set by genuine low voltage at pin 25 of the module connector. Check battery condition and the fusible link at the engine bay fuse box before condemning the module.
• 00526 — Brake Pressure Sensor (G201): Signal Outside Tolerance — the pressure sensor is internal to the hydraulic unit. This code appearing without any brake work having been done recently is a strong indicator the module/hydraulic assembly is failing internally.
• C1513 / C1514 (generic OBD-II format) — Left/Right Rear Wheel Speed Sensor Circuit Fault — these generic codes mirror VAG 00283/00282 when read on a non-VAG scan tool.

When codes 00283 and 00282 appear together with 01130 and 00526, and all four remain after clearing with the ignition off and back on, the module itself is the most likely source. A single sensor code that clears after a drive cycle almost always points to a sensor or wiring issue rather than the module.

OEM Part Numbers for the Audi A4 B8 ABS Module

The correct module depends on engine variant, drivetrain (FWD or quattro) and equipment level (standard ABS versus full ESP with hill assist). Part number matching is not optional — a module with a different hardware number will require variant coding that may not be possible without the dealer tool, and a module from a quattro car fitted to a FWD car will log persistent drivetrain incompatibility codes.

• 8K0 614 517 R — 1.8 TFSI and 2.0 TFSI FWD, standard ESP 8.0 fitment, early B8 production (2007–2009)
• 8K0 614 517 M — 2.0 TDI FWD variants, 2008–2010 production
• 8K0 614 517 BK — 2.0 TDI and 2.0 TFSI quattro, mid-production, Bosch ESP 9.0 unit
• 8K0 614 517 EH — 3.0 TDI quattro, late production (2011–2012), includes hill descent assist variant coding
• 8K0 614 517 CC — 2.0 TDI FWD, post-2010 facelift, revised pump motor housing

The hardware number suffix (the letters at the end) must match or be confirmed interchangeable by part number cross-reference before fitting. GiantParts lists tested OEM units with the full part number so you can confirm fitment before shipping.

Affected Vehicles and Production Periods

The A4 B8 ran from late 2007 to 2015, but the 1990–2012 production window relevant here covers the initial and facelift (B8.5 from 2011) variants. Engine lines affected include the 1.8 TFSI, 2.0 TFSI, 2.0 TDI 143PS and 170PS, 3.0 TDI, and 3.2 FSI. The quattro variants share the same module housing but different internal calibration data. The S4 B8 (3.0 TFSI) uses a separate part number with higher pressure thresholds. A related diagnostic guide is Audi A4 B8 ABS Module Failure: Symptoms and Repair.

The Audi A5 8T, Q5 8R and Audi S5 share the same ESP module family on the B8 platform, but the part numbers are not directly interchangeable without confirming the calibration variant. Do not assume platform sharing means bolt-in compatibility — it does not on this generation.

Test Sequence: Separating Module Failure From Wiring and Sensors

Follow this order before ordering a replacement module:

1. Read all codes with VCDS or equivalent VAG tool — a generic OBD-II reader will miss address block 03 sub-faults. Note which codes are static (present every key cycle) and which are intermittent.
2. Check supply voltage at the module connector — with the ignition on, pin 25 should read battery voltage (12.5–14.2 V depending on charging state). Below 11.5 V here will set 00668 and can suppress pump operation.
3. Inspect wheel speed sensor wiring at the rear axle — the harness runs along the trailing arm and chafes against the subframe on high-mileage cars. Pull the sensor connector and check resistance: a good inductive sensor reads 900–1500 Ω. Active sensors need supply voltage checked at pin 1.
4. Check the reluctor rings — remove the rear wheels and inspect the ABS tone rings on the inner CV joint flange. Cracked or missing teeth cause exactly the same codes as a failing module input channel.
5. Check CAN bus integrity — if the module is logging CAN timeout faults alongside sensor faults, address the gateway or bus wiring first. A module cannot self-heal a broken bus.
6. Live data test of the pump motor — in VCDS measuring block 003, activate the pump motor via output test. If the motor does not spin and supply voltage is confirmed good, the internal driver is likely failed.

Only after steps 1–6 rule out external causes should the module itself be replaced. A used tested OEM unit is the correct replacement; aftermarket remanufactured units for the B8 have a notably poor track record for the internal pressure sensor calibration.

Frequently Asked Questions

Can the Audi A4 B8 ABS module be driven with fault codes active?

The car remains driveable, but ABS, ESP, hill hold assist and in some cases electronic brake force distribution are all deactivated when the module is in fault mode. Braking distances are longer and the car will not assist in a slide. This is a safety concern, not just a warning light issue — do not delay diagnosis on a daily driver.

Does a replacement ABS module on the A4 B8 need coding?

Yes. The module requires variant coding to match the drivetrain (FWD or quattro), engine type and equipment level. This is done in address block 03 using VCDS or ODIS. An incorrectly coded module will store 01044 and may not allow the pump to activate. The basic adaptation also needs to be run after fitting to clear any residual fault memory. For additional context, read What Happens When the Audi A4 B8 Parking Aid Control Module Fails.

Will a module from a B8 A5 fit the A4 B8?

The hydraulic unit physically fits — the mounting and brake line connections are shared across the B8 platform. However, the part number suffix differs because the pressure calibration and yaw rate thresholds vary between body styles. A direct swap without confirmed part number compatibility will usually result in persistent ESP plausibility faults. Always match the full part number.

Can a failing ABS module on the A4 B8 cause a no-start?

Not directly — the ABS module does not sit in the engine start path. However, if the module is drawing high current due to an internal short, it can flatten the battery overnight and cause an apparent no-start. Measure the quiescent current draw with the module connected and disconnected if you have an unexplained battery drain alongside ABS codes.

Is it worth repairing an A4 B8 ABS module rather than replacing it?

The internal pressure sensor and the pump motor driver transistors are the common fail points. Some specialist electronics shops repair the pump driver, but the internal pressure sensor is not serviceable separately from the hydraulic unit. If the fault is limited to a sensor input channel or a pump driver, repair is feasible. If the internal pressure sensor has failed, the entire hydraulic assembly needs replacement — repair is not economic in that case. A used tested OEM unit typically costs less than a specialist repair when the hydraulic unit is involved.

Find tested OEM electronic parts and modules at:
https://giantparts.eu/

Related diagnostic guides and OEM parts

• Audi A4 B8 Cluster Replacement: Mileage and Safe Driving
• Audi A4 B8 Instrument Cluster Faults: Symptoms and Repair

Related available product: 8D0907389D VW AUDI A4 B5 ABS ECU Control Module 0265109463 – OEM Used & Tested

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