The Engine Control Unit or Module (ECM) plays a vital part in the performance of virtually every modern vehicle. Simply described, the ECM’s role is to monitor the network of sensors around the car, just like a main computer, to ensure the car performs as it should. If something goes wrong, the ECM uses the information it collects to tune the engine conditions or, if it cannot, the car will show symptoms of a deeper problem. When there’s a problem, the ECM will trigger the check engine light for the driver and generates a trouble code that a mechanic can diagnose using a special scanner tool.
In newer vehicles, most of the functions of the car are controlled by the ECM, and can usually be accessed by certified shops, dealerships and Volvo Specialists to fix and update programming issues. Some of the symptoms you may experience are:
- Check Engine Light comes on
- Engine Stalls or misfires
- Engine Performance issues
- Car not starting or difficult to start
Common symptoms of a failing ECM include:
ECM-711A, ECM-720B or 918A “ECM Internal Fault”, E-000 and E-003 “Communication Faults”, codes for coils, injectors, outside temp, O2 sensors, MAF, coolant and accelerator sensor pedal codes. Problems with engine cooling fan not activating.
If you experience any of these listed above and your ECM has been diagnosed as needing to be repaired or replaced, you can find your Volvo ECM application here. For the specific Volvo Models listed (S80, S60, S70, V70, XC70, XC90 or C70) you can use the Denso P2 or Bosch P2. In order to get it replaced or repaired, you’re going to have to get the ECM removed. Let a professional help you if you’re the owner of the vehicle, but it you’re the mechanic, here’s how to do it step-by-step.
All P2 Platforms
- 1999-2006 S80
- 2001-2009 S80
- 2001-2007 V70, XC70
- 2002-2014 XC90
- 1999-2000 S70, V70, C70
This is the demonstration to remove the P2 models. Open the hood and look to the front of the engine area on the right side of the vehicle. This is where the power steering, power steering fluid reservoir and coolant reservoir is located also. Look for a plastic cover.
Unclip the cover and remove it. Inside the cover are two modules- one for the TCM and the other for the ECM. The one that says TEMIC is your TCM or your Transmission Control Module. The other labeled BOSCH or Denso is your Engine Control Module or ECM.
There is a special tool that’s required to remove these modules with. The part number from Volvo on this tool is V9995722 and it is relatively inexpensive. If you’re doing a lot of work on modules like this, then it’s a must-have tool. This is what it looks like:
Now inside this box there are two slider rails that basically lock into the ECM and as you pull it back they pull the tabs and lock the ECM in. To remove the ECM it will be the opposite. Just slide the tabs forward and release the ECM.
There are some grooves at the base of the module that the tool aligns with. Stick the tool in downwards and press down to make sure that it is going to stay inside, pushing it in as far as it can go. Then slide and push forward to release the tabs and allow the ECM to come out easily. See how here.
IMPORTANT NOTE: Whenever you’re removing these engine modules and you have shut off the vehicle, it will still stay powered up for approximately 2 minutes. It’s imperative that you wait those two minutes after shutting off the vehicle to make sure the relay is powered off as it will not automatically power off as soon as you shut off the ignition.
Physically inspect the unit. Ensure that all the pins are in good shape. Look to see that nothing is bent or out of place and that there is no corrosion. Also inspect the terminals inside the box, called the wiring harness terminal. Make sure that there are no foreign objects in there and that it’s not dirty. If you feel that all is well, then basically leave the terminals as is.
Inside the box some persons like to add some dielectric grease. If you’re going to do it, we recommend using a high quality product. One decent product that we use quite a bit is called Stabilant 22. It’s a good quality product but fairly expensive- a good investment to make especially for shops.
And that’s basically the method for removing the ECM units safely.
IMPORTANT NOTE: DO NOT touch them with your fingers. Static electricity can basically wipe out these ECM units. If you’ve got enough of a charge built up in your body and you touch these terminals, you can zap out a component internally very quickly.
Step 5: Re-install your new or repaired ECM
There are two locating pins at the base of the module and there are two holes at the bottom of the box where these pins fit into. When you’re reinstalling this, there are some guides that these sides fit into. Start by aligning that and make sure the locating pins go into place. Push it down firmly. You want to make sure that it’s going to lock into those little tabs on the sliders. Basically lock the unit down.
Now re-install the module in reverse of the removal. The removal tool goes in, and just slightly put a bit of pressure to pull backwards. Lock it into place and make sure it’s pushed all the way back, and then slide it out.
NOTE: Whenever you replace an ECM or you load new software into an ECM, it’s a good idea to do an adaption of your throttle. From 2002 and up they have stopped using ETMs on the turbo models and now use electronic throttle bodies (ETB). Once the ECM has been replaced or if there has been a software reload done to the module or an upgrade, it’s a good idea to adapt the throttle body again.
Summary of Key Notes
1. Part number of the tool is V9995722
2. Wait approx. two minutes after the engine of the vehicle has been shut off before you remove the ECM. It allows the relay to be powered down.
3. If by chance the electric cooling fan is on when you shut off your vehicle, you have to wait until the fan shuts off and then wait another extra two minutes after the fan stops working, then it will be safe to remove that ECM.
4. DO NOT touch it with your hands. Static electricity can damage these units.
5. Anytime you replace an ECM or put new software into it, it’s a good idea to adapt the throttle body.
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