Audi & Volkswagen (VW) Bosch 5.3 ABS Pump & Controller ECU Common Faults & Repairs
A very common fault on practically all VW’s & Audi’s is the ABS pump and controller module failing. We repair all types of ABS pumps & controller modules but this blog post in particular is about the very common Bosch 5.3 unit which is seen commonly failing on the following vehicles:
- 1996 – 2001 Audi A4, A6, S4
- 1996 – 2001 VW Passat
When it fails, the ABS light will appear on the dash and the most common faults with these units is no communication and wheel speed sensor faults. If that’s the problems you’re having then no doubt we can repair it for you, saving you £££’s on what you’d be paying if you had bought a brand new unit & because we’re repairing your own unit, you don’t have to pay to get it recoded or programmed either.. it’s all plug & play when you get it back and fully covered by our 1Yrs warranty.
Even if the fault you’re getting on your unit is not as described by us, give us a call anyway.. we try to keep these articles as accurate as possible at the time of publishing but to reduce confusion we only list the most common failures. Other faults are also:
- ABS Light On
- No Communication
- Wheel Speed Sensor Faults
- Juddering When Braking
Whatever the faults, give us a call today on 0203 815 9441 and let us quote you happy, we even carry many of the most common ABS units in stock ready to be dispatched same day.
All BOSCH ABS units start with either 0265 or 0273. If it’s an ATE ABS unit then the part numbers will start with 10 and OEM part numbers do vary. Whichever unit you’ve got, we always suggest contacting us with the full part numbers first to get an accurate quote for the cost of repairs or to find out if we’ve got a replacement unit in stock.
Ajaz is a seasoned automotive electronics engineer with deep expertise in remanufacturing vehicle electronics. He has developed skills in all areas of the automotive field, from rebuilding hydraulic steering components, and mechanical gearboxes and reworking intricate vehicle electronics. Ajaz also acquired Bodyteq, a London-based vehicle bodyshop where he has developed extensive knowledge in automotive refinishing.
Alongside his automotive career, Ajaz has built a career in the IT industry, gaining accredited certification as an AWS Certified Cloud Practitioner, Cloud Architect, and Search Engine Optimisation (SEO) specialist.
Dear Sirs,
I have those problems with mit ecu bosch 5.3 (audi A6) i have performed several tests and check that everything is ok but the ecu is damaged.
I sent it to a company called ECUTesting and they told me that it has not possible repair.
Is it possible to by a used or repair unit from you ?!?
Hope to hear from you soon.
thanks and best regards,
Rui Leiria (portugal)
Hi Rui,
Sure please send us an email with all the part numbers on your Audi A6 Bosch 5.3 ABS unit and we will match up a replacement for you. Did ECU Testing tell you why they couldn't repair it? What problem was you having?
There's still a good chance we can save your unit even if another company couldn't.. maybe they didn't have the parts to repair it..
Hi my VW Passat TDi 05 plate when driving after about 5 or 6 miles all 4 wheels start to smoke and brakes bind – suspect abs pump! Don’t know whether electrical or hydraulic fault, ABS light comes on when it happens, be grateful if you can quote on either electrical part or hydraulic part overhaul or both thanks Russ.
Hi Russ,
It will be a hydraulic problem and not necessarily the ABS pump itself but it will need to be diagnosed correctly. Below I have listed for you the steps you need to carry out or take to the workshop for reference to aid them in finding the fault.
Brakes bind – Only after driving for a while.
Symptoms: Brakes are free at the start of a journey, but gradually bind or lock on as you drive.
Cause: Heat is gradually generated as you apply brake pressure. The heat will be transferred to the brake fluid and as this temperature increases, the fluid will expand. Under normal circumstances, this expanded fluid returns to the master cylinder reservoir. If the expanded fluid cannot return to the reservoir, pressure builds up and this will cause the hydraulic brakes to be applied. As the heat builds up, the pressure applied on the brakes will also increase. When the fluid cools down, pressure reduces and the brakes release.
Solutions: Take a short drive until the brakes begin to bind, once they are binding then take the vehicle into a workshop and follow these steps.
Step 1.
With the brakes stuck on, slacken, by two to three threads, the nuts that hold the master cylinder to the servo. Then press and release the brake pedal. If the problem persists proceed to step 2. If the brakes are free after you\’ve done this, the problem lies with the servo or the mechanical links to the pedal. Check that an incorrectly adjusted brake light switch is not holding the pedal on slightly. If the pedal has a link rod to the servo, check that this is well lubricated an moves freely. If the problem is not caused by the brake light switch or by the link rod sticking, it\’s possible that the link rod or servo push rod have been adjusted incorrectly. Otherwise, the servo is probably faulty.
Note: Just in front of the master cylinder valve seals are small holes; these are compensating ports. With the brake pedal released, the master cylinder pistons should be fully home; otherwise the compensating ports will be blocked by the valve seals.
Step 2.
Slacken one pipe at the master cylinder for each circuit in sequence. (Use a rag to stop fluid squirting everywhere because brake fluid works like paint stripper). This will release any pressure in that circuit. If the problem persists proceed to step 3. If the brakes release now, then it\’s highly probable that the master cylinder seals have swollen through contamination and are blocking the compensating/relief ports.
Step 3.
Feel each wheel and start with hottest wheel/brake first. Careful, things will be very hot! Slacken the bleed nipple/s on the caliper or wheel cylinder. If the brakes do not release, proceed to the next hottest wheel and repeat. When the brakes release, the problem is a faulty flexible hose attached to that wheel.
Note: It is not uncommon for the inner wall of a flexible hose to collapse. When this happens, the collapsed wall can act like a one-way valve and can restrict the return of fluid.
Step 4.
If the brakes are still stuck on, release the handbrake and start again!
IMPORTANT: Remember to re-tighten all pipes/unions, nuts/bolts and bleed nipples.
I hope this helps, you are always welcome to bring the vehicle in to us and our hydraulic engineers will look over it for you.
Best of Luck,
Support Team
Sinspeed Ltd
We are working on my buddies 2000 VW Passat, we are missing the signal for the right front wheel speed sensor. We have replaced the sensor and ohmed the wire from the sensor back to the abs contol module and both wires are good. Not sure if it goes anywhere else or if the control module is the problem?
Hi
I have a ABS fault with my w reg VW Transporter. Checked code and it came up with front right and rear right speed sensor. I have fitted new sensors but fault still there. When checking wiring I found that both connector terminals were going to earth. I took off the main connector from pump and checked sensor terminals and feed the wire and all this seemed ok, but as soon as I connected the main plug back on to the pump, this gave me the earth in both wires, does this mean the pump and module is faulty?
Hi John,
Yes, this indicates that the ABS controller is at fault, however, the unit can be repaired as a pose to replacing it for new/used parts. We can repair these with a full 2 year warranty at a very cost effective price. For more information call our offices on 0203 815 9441 or if you can send us an email, a member of staff will get right back to you with a quotation.
Many Thanks,
Admin @ Sinspeed Ltd
Hi,
I live in Macclesfield and have a vw golf plus (2005) 27,000mls. with abs problem ,part 1K0698517B and light showing always ESP.
What price are we talking about for repair or replace?
Kind Regards, Alan
Hi Alan,
We don't put prices on our site but please email us or call us on 0203 815 9441 to get an instant quote.
Best Regards,
Tech Team
Sinspeed Ltd