ECM Replacement
This was a months long proces for my 2015 SR5 (about 165,000 miles)
- This past summer, while on a 6 hour drive back home, the CEL and TRAC OFF light came on. When I was able to pull off the interstate, I unplugged the battery for about half an hour. About ten minutes down the road, the light came back on and it went into limp mode. When it was able to get into an Autozone parking lot, it was diagnosed to have a VVT Solenoid or Crankshaft Position Sensor fault, with zero help from the employee on finding the part. I was able to pull the parts out, clean them, and the faults went away. The vehicle went about 2 more hours before the CEL came on alone flashing and I experienced a misfire. The vehicle was towed back to my house, where it now showed that it was a camshaft position overretarded, with a new fault for O2 sensor heater circuit.
- I changed out every VVT, Crankshaft position sensor, and sparkplugs/coils.
- About a month ago, the CEL and TRAC OFF lights came back on for P0057 and P0161 (B2S2 O2 heater circuit). It showed both of those codes as "permenant" and P0161 as "stored" and "pending." I had previously put in a Bosch O2 sensor, so I put in a new Denso sensor. The CEL came back on...
-Unsure if I just received a bad O2 sensor, I tried another Denso sensor, and the light came back on, with all the codes again showing as above.
- I inspected wiring for any chaffing, the A/F fuse, the Integrated Relay for resistance based on the "ALLDATA" troubleshooting guides. Everything was good.
-Here is where I may have gotten "fleeced" by a bad dealership. I brought the vehicle to the Toyota Dealership for a diagnostic ($175), and to hopefully pinpoint the issue. They said it was an O2 sensor issue and recommended I put in the OEM part... Which was already in. They refused to work on the vehicle until I put in a "Toyota" part from their service department. Not sure why I did it, but I fancied their request and purchased the sensor ($200) that said "Denso" on the part. To not pay $600 for installation, I did it myself in about 15 minutes. The CEL came back on as expected.
- I brought it back to Toyota, where they further troubleshooted it down to the Integrated Relay. I opted to have that replaced ($350) because the technician claimed that they tested it to be bad, and there wasn't really a labor charge for installation. Once they called and said that the part was replaced, the vehicle was test ran, and it was "running great," I went and picked up the vehicle. About a mile down the road, the CEL came back on. I checked the trip meter, and the vehicle had only been driven 2 miles since the battery was re-installed after the relay replacement. No way they ran a full drive cycle and checked for any codes.
- This time, I was obviously not happy, because I was $725 into "troubleshooting" at the dealership and it seems like they didn't do any actual troubleshooting, and lied about the condition of the vehicle. They finally did resistance checks on wiring, which checked to be okay and left the ECM as the only possible issue in the circuit. The quote for this was $1400, and a call to another trusted mechanic in town was $2000.
- With a lack of trust for the mechanic, and already being deep into this issue, I started looking at options for me to do this myself. I figured that if I bought a used ECM with a warranty, if it didn't work I could return it and buy the more expensive option. LKQ had a used one from a similar model for $165. I couldn't find any information on Gen 5 vehicles having similar issues, but a little bit on Gen 4, and other Toyota models. From what I read, syncing the immobilizer was the only real "required" thing to do, and VIN matching may only be necessary for Emissions testing, or possibly selling.
- I recieved the ECM, and begun my work. Unplug the battery, first! For removing the glovebox to access the ECM, I followed
this video which is required to access the ECM. Once the trim and glovebox were removed, the ECM was unplugged, and a bolt on the top/nut on the bottom were removed to take it out. There was another item on that bracket, that was just removed via a clip and slid right off.
- You have to move the metal brackets from the old ECM to the new one. This was a few phillips head screws, and easy. Just install it back in, and plug in the connectors/battery.
- Don't put all the trim back together until after you sync the immobilizer in case there was an issue... You wouldn't want to have to take everything back apart.
- The immobilizer sync isn't hard, I just followed
this video for the steps. It takes about half an hour for this process.
- After everything was done, the vehicle started back up, and ran for about half an hour without an issue. While it was running, I reinstalled all of the trim and glovebox.
It has ran great since, including two trips of about 1.5 hours and normal daily drives. Now the next steps aren't completely necessary, but I just did it because I wanted to ensure there weren't any issues if I were to sell it in the future/move somewhere that requires emissions testing.
- I learned that diagnostic tools that are capable of changing the VIN need the "Techstream" software, or there are some OBD tools that can do it.. most are very expensive. I was able to find
this tool on Amazon for about $150 on sale I have heard you can buy a cable that can connect to a computer with some downloaded software as well, but this was easier for me. I confirmed with the seller that it was capable of re-writing the VIN. If it didn't work, I would just return it.
- I got the diagnostic tool in, and was able to go through menus to re-write the VIN. There aren't any real instructions on how to, I just had to go through menus until I found the option. I was able to match the VIN written in the ECM to the vehicle. Again, this is not required, and did not affect the vehicle performance. Someone can comment and maybe find a cheaper or easier option.
In conclusion, I just wanted to write all of this because I couldn't find any information regarding Gen 5s with this issue. I hope it helps others with similar cases to find cheaper options for an ECM replacement than what dealerships/mechanics charge. After quotes of $1400 and $2000 for new ECMs, I was able to find an ECM for $160 and a diagnostic tool for $150 (again, not necessary). The entire replacement process takes about 2 hours on the conservative side. This saved me over $1000.
