Showing articles & questions for topic
ECU (Engine Control Unit)

On cars built after the late 1990's, replacing an ECU is a much bigger deal than just plugging in a new box. The ECU has to recognize the serial number of the car and the other modules in the car....

The security system warning light should not illuminate once the vehicle is started and you are driving. If the light does illuminate, that means there is a malfunction in the security system. Obviously, if this problem started immediately after you...

You should not replace any parts, at all, unless the part is diagnosed as not functioning. ECU's rarely fail (fully 50% of warranty returns on ECU's have absolutely nothing wrong with them). If there is a spark at the plug...

If the two posts are indeed specified for jump starting, then the answer is "yes" you can safely install a 12 volt car battery there at the remote posts while you remove and replace the permanent car battery. Electrically, all...

Hi and thanks for contacting YourMechanic. First, remove the ground cable from the battery and let it stay off for 12 minutes. Then hook up the battery cable and retry the key. If your vehicle still gives you the same...

Hey there, thanks for writing in about your 2006 Land Rover LR3. Unfortunately, this is a specialized service only available through Land Rover service centers, and not a cost estimate readily available to us here at YourMechanic. I recommend requesting...

Hi there. From the description you have provided, your vehicle Check Engine Light on with lots of warnings and exterior lighting acting weird, sounds like there may be a charging system related problem (https://www.yourmechanic.com/services/electric-problems-inspection). I would recommend not driving your...

Hello and thank you for contacting YourMechanic. The ECU is under your passenger's side seat. You can gain access to it by simply sliding the seat all the way forward and removing the plastic cover from the ECU. You can...

The pink/light green wire in ECM pin 2 on the connector will ground the wire internally to the ECM to turn on the Check Engine Light. You could test the wire with the key on and it should have battery...

If your ECM is failing (https://www.yourmechanic.com/article/symptoms-of-a-bad-or-failing-engine-control-module-ecm) or has failed, it shouldn't be extremely difficult to find a good shop to rebuild or replace them. There are a number of electronic rebuilders who rebuild ECMs (w/warranty). Also, there are a number...

The electronic control unit (ECU) used in today’s cars and trucks is used to control the engine and other components’ functions. An ECU is a computer with internal pre-programmed and programmable computer chips that is not much different from a...

Hello there. No start conditions are one of the most common faults. If the car will not communicate with the OBD-II DLC port, then this typically means there is a fault between the connector and the ECU. This could be...

Hello, and thank you for writing in. The vehicle likely did not suddenly develop all of these problems. Oil leaks in particular happen due to excessive engine wear. The spark plugs and their coils tend to be regular maintenance with...

Hi there. First check the battery and make sure that there is 12.6 volts. If the battery is low, then the battery will need charged before testing again. Check the wiring from the battery to the fuse box and make...

There is one thing I don't think you have listed or have checked. That would be injector pulse. You can have fuel pressure but without injector pulse from the ECU, the injectors will not open and the cylinders will not...

The engine control unit (ECU) is a possible cause of the O2 sensor (https://www.yourmechanic.com/services/oxygen-sensor-replacement) fault codes but not the most likely. Your vehicle is equipped with 4 O2 sensors. Bank 1 is the driver's side. Bank 2 is the passenger...

As you know, your car is equipped with wheel speed sensors at each of the four wheels which monitor wheel speed while relaying this information constantly to the ABS and traction control system which are controlled by the car's ECU....

Hi there, check the A/C relay for being stuck in the "On" position. Relay contacts degrade over time and use, and can stick together when burned. The result would be the A/C light staying on, even though you press the...

Hi there. There could be several reasons for your vehicle's intermittent no start issue. From the description you have given, I would not think the ECU (electronic control unit) is your vehicle's problem. Assuming the ECU is not recognizing the...

Hello. The ECU could not have been damaged by moving injectors to different cylinders. The injectors are not programmed to be in a particular cylinder of the engine. Having only two injectors reconditioned is the most likely cause for running...