Skip the auto shop - Our mechanics make house calls

Q: Unplugged wires ECM DTC

asked by on

I purchased a used 4WD truck with the only problems I thought were a dead battery and no air conditioning. My short test drive proved nothing was wrong. So I bought a new battery for it and drove it home. Then the "service engine soon" light came on and the speedometer quit working. Then I saw that the ABS wires were all unplugged for the ECBM. I plugged them in and the ABS warning lights came on and stayed on. I put in a new vehicle speed sensor and engine control module. It didn’t do much good, except the new ECM described a list of DTC codes having to do with the ABS. There is no speed sensor input on either front wheel, erratic rear speed sensor, pump relay out/open, brake switch DTC, etc. I need some advice because this truck is a mess of wires upon further investigation, and it’s above my skill level. I have unplugged plugs up the ying yang under the lower dash beneath the steering wheel and a couple over the AC evaporator. I don’t have whole lot of money either. But do you recommend I take it to a dealer or small repair shop to be fixed?

Hello. It is a common issue for the ABS control module to go bad on these trucks. Either the modules are ridiculously expensive or they just aren’t available anymore. That is why the connector was unplugged. That is the "cheap" fix. The speedometer issue could very well be the actual cluster itself.

Either that or there is a wiring issue between the sensor and the instrument cluster. Sometimes a new ECM will need to be programmed for everything to work properly. I would focus on getting the speedometer working. For more help tracking down the problem, a certified professional from YourMechanic can inspect the electrical system in your car to let you know what needs repair.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. Unplugged wires ECM DTC

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Cost to replace rear differential on a 2014 Tacoma TRD 4x4?

Billing question was sent to CS for the cost to replace the rear differential on a 2014 Toyota Tacoma TRD 4WD.

Q: Car Alarm goes off when driving - 2012 Toyota Corolla

Hi and thank you for contacting YourMechanic. Car alarms are tricky and can drive people crazy. To my knowledge, there are several ways that the car will arm the alarm with the key in the ignition. Go around the vehicle...

Q: Driveshaft assembly

Hello, thanks for writing in. The driveshaft assembly is composed of the driveshaft, U-joints and snap rings. Both ends of the driveshaft connect to the output shaft and differential via yokes. If you would like help with this replacement, consider...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...