zordak
zordak Reader
7/2/22 11:49 a.m.

O.K. I have an 06 Eclipse with the V6. I died on the road yesterday. I got it home and started looking at it this morning. Hooked up my scan tool (which I have used on this vehicle before) it says it cannot communicate with the vehicle. I pulled a coil(coil on plug) hooked up my spark checker and did not see a spark when cranking the engine. I suspect a bad ecu. I cannot find any information on further checks to confirm a bad ecu. Also it sounds like a factory type scan tools is required to replace one. Any advise or information would be helpful TIA.

 

Tom Suddard
Tom Suddard GRM+ Memberand Director of Marketing & Digital Assets
7/2/22 11:53 a.m.

I'd start with the basics, here's one of our how-tos:

https://grassrootsmotorsports.com/articles/troubleshooting-101-basic-steps-when-your-car-wont/

I'd suggest checking for spark by spraying some carb cleaner in. From there, you can move on to diagnose fuel or timing.

Javelin
Javelin GRM+ Memberand MegaDork
7/2/22 11:57 a.m.

Battery voltage and amperage? Also check your battery cables and where they go to. I've had similar issues with a corroded ground.

zordak
zordak Reader
7/2/22 12:23 p.m.

The car cranks easily I suspect plenty of battery voltage and good grounds. As stated above using a home made spark checker and there is no spark. 

EvanB
EvanB GRM+ Memberand MegaDork
7/2/22 12:32 p.m.

I helped with an Evo X that had similar symptoms but wouldn't crank. No ecu communication and the fan was running with key on. Ecu was fried and had to go to the dealer to get a new one flashed.

Dusterbd13-michael
Dusterbd13-michael MegaDork
7/2/22 12:32 p.m.

Sounds like either a bad ECU, or wiring issue. Have you checked fuses?

zordak
zordak Reader
7/2/22 12:45 p.m.

not yet. there is power to the data connector. 

Mndsm
Mndsm MegaDork
7/2/22 1:04 p.m.

I would guess bad ecu if the code reader failed to connect, or something bad in the harness along the way. You have critters?

zordak
zordak Reader
7/2/22 1:40 p.m.

No critters no sign of defective wiring.

Slippery
Slippery GRM+ Memberand PowerDork
7/2/22 1:57 p.m.

Does that car use a crank position sensor?

Streetwiseguy
Streetwiseguy MegaDork
7/2/22 2:27 p.m.

Ecu is about the 63rd thing that makes a car not run...

buzzboy
buzzboy SuperDork
7/2/22 3:28 p.m.

Crank Position Sensor would be my first guess.

06HHR (Forum Supporter)
06HHR (Forum Supporter) Dork
7/2/22 4:03 p.m.

Unfortunately the way to check for a bad ECU is generally to swap in a known good one. Check fuses, fusible links and grounds. I think the tipoff is that your scan tool won't connect, but id exhaust the obvious before getting a replacement.

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
7/2/22 9:32 p.m.

Computer not getting power will cause no communication, too.

zordak
zordak Reader
7/4/22 4:12 p.m.

O.K. to close this out, I started with checking fuses. Found the #9 fuse under the hood to be bad. replaced fuse and it blew on trying to restart. A google search brought up that the O2 sensors are on that fuse. I disconnected the sensors (all 4) and replaced the fuse again and it started right up. I am in the process of replacing all 4 sensors as this thing has over 200,000 mi I figured it would be best. Side note the crank and cam position sensors are also on this fuse.

WonkoTheSane
WonkoTheSane GRM+ Memberand UltraDork
7/4/22 5:05 p.m.
zordak said:

O.K. to close this out, I started with checking fuses. Found the #9 fuse under the hood to be bad. replaced fuse and it blew on trying to restart. A google search brought up that the O2 sensors are on that fuse. I disconnected the sensors (all 4) and replaced the fuse again and it started right up. I am in the process of replacing all 4 sensors as this thing has over 200,000 mi I figured it would be best. Side note the crank and cam position sensors are also on this fuse.

Glad you figured it out, and really glad it wasn't the ECU itself!  Thanks for updating the thread for those of us following along at home. 

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