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?

A: Hello. It is a common issue for the ABS con...

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!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: SUV stops & idles at red lights

I would recommend having your alternator tested. If the voltage regulator inside the alternator has failed allowing the alternator to overcharge the battery, symptoms such as the one your described may occur. These symptoms would be the result of the...

Q: 1.69 amp parasitic draw, previous owner had hitch. Everything stock

The best way to find the draw is to pull fuses out one at a time. This isolates which circuit needs to be diagnosed. You may have a module (computer) that is not going to sleep. I found a technical...

Q: Parking brake stuck on Ford E350.

That is possible. Depending on the brake options you have on the Econoline you either have a 3 cable assembly that runs to the rear brake drums or, if you have a 4 wheel anti-lock brake system, you may have...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...