C0020 ABS pump motor control circuit fault

ABS pump motor control

C0020 in short

C0020 means the ABS module found a fault in the circuit that runs the ABS pump motor. Common causes are a failed pump motor or hydraulic unit, a bad ground, or water in a fuse box. Normal brakes still work, but anti-lock does not; get it inspected soon, and stop if the red brake light comes on.

The anti-lock brake (ABS) system has a small electric pump inside the hydraulic control unit. The ABS module switches it on and watches that it runs. C0020 is set when the module sees that the pump motor circuit is not doing what it was told.

Bulletins point to different causes by make. Ram calls C0020-01 a general electrical failure in the ABS pump motor control on 2017–2018 2500 and 3500 trucks. Ford found a poor ground on 2020 Explorer and Aviator, and water in the battery junction box on 2020–2021 Super Duty. Mazda found a pump motor brush losing contact in heat and humidity on the 2010–2011 Mazda3.

With the ABS light on, normal braking remains but the wheels can lock in a hard stop, and stability control may also be off. If the red brake light comes on too, part of the brake system may have failed.

Most likely causes

  1. ABS hydraulic control unit or pump motor failure

    Supported by vehicle data
    Why it ranks here
    FCA bulletins cover C0020-01 on 2017–2018 Ram 2500 and 3500 and say the hydraulic control unit can be replaced alone.
    What would change this
    Rises on a 2017–2018 Ram heavy-duty truck.

  2. Pump motor brush losing contact in heat and humidity

    Supported by vehicle data
    Why it ranks here
    Mazda bulletin 04-002-13 says the pump motor brush can lose contact in hot, humid weather on the 2010–2011 Mazda3 with DSC, setting C0020:1C with U0415:92.
    What would change this
    Rises on that Mazda3 and when the light comes and goes with the weather.

  3. Poor ground connection to the ABS module

    Supported by vehicle data
    Why it ranks here
    Ford TSB 20-2364 says a poor ground or improper bolt plating at ground G108 can set C0020 on 2020 Explorer and Aviator, so the ABS module may not need replacing.
    What would change this
    Rises on those models built on or before Feb 29, 2020.

  4. Water in the battery junction box

    Supported by vehicle data
    Why it ranks here
    Ford TSB 21-2176 links C0020 with U3003 to water in the under-hood battery junction box on 2020–2021 Super Duty trucks, often with other electrical faults.
    What would change this
    Rises if U3003 is also stored, the engine will not shut off or there are other electrical problems.

  5. Other power or ground fault in the pump motor circuit

    Possible — needs testing
    Why it ranks here
    The Ram and Ford bulletins show both the unit and its power or ground can set this code, so the circuit should be tested before parts are replaced.
    What would change this
    Rises when no bulletin fits the vehicle.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Note which warning lights are on. The yellow ABS light alone is different from the red brake light.

    Low risk

    • IfThe red brake warning light is on with the ABS light

      It meansFCA says part of the brake system may have failed and stopping takes longer. Do not keep driving.

      Go to step 3

    • IfOnly the ABS light (and maybe the stability light) is on

      It meansNormal brakes should work, but anti-lock does not. Have it serviced soon.

      Go to step 2

  2. Check the VIN for open recalls at nhtsa.gov/recalls, and have the codes read with a scan tool that reads ABS codes, noting any subcode and other codes such as U3003 or U0415.

    Low riskTool: scan tool that reads ABS codes

  3. Have a dealer or brake shop test the pump motor circuit, grounds and power feeds before replacing the ABS module or hydraulic unit.

    Best left to a shopTool: scan tool with ABS bidirectional tests

    Warning:Brake system work. Testing and any ABS module or hydraulic unit replacement, including bleeding, should be done by a shop.

Symptoms

  • ABS warning light on
  • Stability or traction control light on
  • Red brake warning light on with the ABS light Gets more serious: stop and have it checked.
  • Wheels lock during a hard stop

How to fix

This is a safety-critical system, so we explain the code but don't give repair steps. Have it inspected by a qualified technician.

Parts and cost context

  • ABS hydraulic control unit:FCA says the HCU can be replaced alone for C0020-01 on 2017–2018 Ram heavy-duty trucks. Labor varies; get a quote.
  • Ground cable fasteners (Ford G108):Ford says a ground repair may avoid a new ABS module on 2020 Explorer and Aviator.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Ram

  • 2017–2018 · 2500

    Supported by vehicle data

    FCA bulletins cover C0020-01 on 2017–2018 Ram 2500 and 3500 and say the hydraulic control unit can be replaced alone. The bulletins are on NHTSA, but whether they are still current is not verified, so it is labelled vehicle data rather than confirmed.

    Where it is:ABS hydraulic control unit

  • 2017–2018 · 3500

    Supported by vehicle data

    Same FCA bulletins as the 2500. The bulletins are on NHTSA, but whether they are still current is not verified, so it is labelled vehicle data rather than confirmed.

    Where it is:ABS hydraulic control unit

  • 2017–2018

    Possible — needs testing

    Context only: Recall 24V-896 covers hydraulic control unit failure that can disable ABS, ESC and traction control on 2017–2018 Ram 2500, 3500, 4500 and 5500. The recall record does not name C0020, so whether it applies to a given C0020 truck needs a VIN check and dealer diagnosis.

    Where it is:ABS hydraulic control unit

    Related recall campaigns: 24V-896

  • S2005000004Status unverified

    C0020-01 ABS pump motor control, general electrical failure

    2017–20182500, 3500 · issued · NHTSA 10175691

    Service publication for C0020-01 on 2017–2018 Ram 2500 and 3500. Only the NHTSA flat-file summary was reviewed, not the bulletin itself.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • S2005000004 Rev. CStatus unverified

    C0020-01 ABS pump motor control, general electrical failure (Revision C)

    2017–20182500, 3500 · issued · NHTSA 10181550

    Revised version of the same publication. Only the NHTSA flat-file summary was reviewed, not the bulletin itself.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • 9004246Status unverified

    ABS module: HCU can be replaced alone for C0020-01

    2017–20182500, 3500, 4500 · issued · NHTSA 10175611

    When ordering ABS module PN 68347098AB or later for C0020-01, the hydraulic control unit can be replaced by itself. Only the NHTSA flat-file summary was reviewed, not the bulletin itself.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Ford

  • 2020 · Explorer

    Supported by vehicle data

    Ford TSB 20-2364 says a poor ground at G108 can set C0020 on 2020 models built on or before Feb 29, 2020, and the ABS module may not need replacing. The bulletin is on NHTSA, but whether it is still current is not verified, so it is labelled vehicle data rather than confirmed.

    Where it is:Ground G108

  • 2020–2021 · F-250 Super Duty

    Supported by vehicle data

    Ford TSB 21-2176 links C0020 with U3003 to water in the battery junction box on 2020–2021 Super Duty trucks. The bulletin is on NHTSA, but whether it is still current is not verified, so it is labelled vehicle data rather than confirmed.

    Where it is:Battery junction box under the hood

  • TSB 20-2364Status unverified

    ABS lamp on with C0020: ground connection at G108

    2020explorer · issued · NHTSA 10186387

    The ABS module or HCU may not need replacing; replace and tighten the ground cable fasteners at G108. Also covers the Lincoln Aviator and Police Interceptor Utility. Only the NHTSA flat-file summary was reviewed, not the bulletin itself.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • TSB 21-2176Status unverified

    Electrical faults and ABS lamp with C0020 and U3003: water in battery junction box

    2020–2021f-250, f-350, f-450, f-550 · issued · NHTSA 10200732

    Inspect the under-hood battery junction box for water and replace it if water is found. Only the NHTSA flat-file summary was reviewed, not the bulletin itself.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Mazda

  • 2010–2011 · Mazda3

    Supported by vehicle data

    Mazda bulletin 04-002-13: on cars with DSC, the ABS pump motor brush can lose contact in heat and humidity, setting C0020:1C with U0415:92. The bulletin is on NHTSA, but whether it is still current is not verified, so it is labelled vehicle data rather than confirmed.

    Where it is:ABS hydraulic unit

  • 04-002-13Status unverified

    ABS warning light on with C0020:1C and U0415:92

    2010–2011mazda3 · issued · NHTSA 10097406

    Pump motor brush in the ABS hydraulic unit can lose contact in heat and humidity; the brush material was changed. Only the NHTSA flat-file summary was reviewed, not the bulletin itself.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • U0415A module received invalid data from the anti-lock brake (ABS) module

    Shares causes Supported by vehicle data

    Mazda lists C0020:1C together with U0415:92 when the ABS pump motor brush loses contact on the 2010–2011 Mazda3 with DSC.

All ABS, traction and stability control codes

C0020 questions

Is it safe to drive with C0020?

FCA says normal brakes keep working when only the ABS light is on, but anti-lock does not, so have it serviced as soon as possible. If the red brake light is also on, have it checked immediately.

Is there a recall for C0020 on Ram trucks?

Recall 24V-896 covers ABS hydraulic control unit failure on 2017–2018 Ram 2500, 3500, 4500 and 5500. The recall does not name C0020, so it may or may not be your fault; check your VIN and ask the dealer.

Do I need a new ABS module for C0020?

Not always. Ford found a bad ground on some 2020 Explorers, and FCA says the hydraulic unit can be replaced alone on some Ram trucks.

Sources and review

  1. 2022 Ram 2500/3500 Owner's Manual: Anti-Lock Brake (ABS) Warning Light — FCA US LLC (Mopar)
  2. FCA S2005000004: C0020-01 ABS pump motor control, general electrical failure — FCA US LLC / NHTSA ,
  3. 2022 Ram 2500/3500 Owner's Manual: Brake Warning Light — FCA US LLC (Mopar)
  4. FCA 9004246: C0020-01 ABS pump motor control, general electrical failure, HCU can be replaced alone — FCA US LLC / NHTSA ,
  5. FCA S2005000004 Revision C: C0020-01 ABS pump motor control, general electrical failure — FCA US LLC / NHTSA ,
  6. Mazda 04-002-13: ABS warning light on with C0020:1C and U0415:92 (Mazda3 with DSC) — Mazda North American Operations / NHTSA ,
  7. Ford TSB 20-2364: ABS lamp on with C0020, ground connection at G108 — Ford Motor Company / NHTSA ,
  8. Ford TSB 21-2176: engine will not turn off and electrical faults, ABS lamp with C0020 and U3003, battery junction box water intrusion — Ford Motor Company / NHTSA ,
  9. NHTSA Recall 24V-896 (FCA C4B): loss of ABS/traction control from hydraulic control unit failure, 2017–2018 Ram heavy-duty — FCA US LLC / NHTSA (via vehiclesafetyrecalls.com) ,
Last reviewed
Written by
Saurabh K.
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