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?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  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: Four-wheel drive thumping noise. 2006 Mazda B4000

Hello. It sounds like the transfer case is going bad causing the thumping noise you are hearing. The transfer case transfers power to the front wheels so that all four tires are working during four-wheel drive. If the transfer case...

Q: I have changed the camshaft position sensor, crankshaft position sensor, spark plugs and plug wires and there still is no fire.

Hi there. If there was a spark around the speed sensor as the engine was starting, then there is a major short in the ignition system. Check all of the wiring grounds and make sure that they all are hooked...

Q: My truck surges at low and idol speeds. Cold or hot. Sometimes quits when put in gear. Very low speed has a miss.

Hello and thank you for contacting YouMechanic. When you unplug the temperature sending unit the problem goes away but the engine light comes on. Check the plug to the sending unit for any corrosion or debris. Look at the pins...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
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...
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...