Mitsubishi Eclipse 4G Forums banner
1 - 11 of 11 Posts

·
Registered
Joined
·
12 Posts
Discussion Starter · #1 ·
I have a 2009 with the 2.4L that after pulling into the driveway the other night the check engine light came on and it started idling rough as hell. I shut it off and restarted it. It started back up but ran rough as hell, tach was at around 1000rpms but it felt like 150-200, it would finally sputter then die but will restart every time. I can move the gas pedal slow or fast, pump the heck out of it, nothing has any effect. It had no cel or codes before this, now it has the following codes...
P0642 Sensor Reference Voltage "A" circuit low
P0606 Control module processor
P2138 Accelerator pedal position sensor 1/2 correlation
P2123 Accelerator pedal position 1 circuit high
P2253 O2 Sensor 1/1 Negative Current control circuit high

I cleared the codes with my scanner, also left the battery unhooked overnight and got back to it tonight. As soon as I turned the key on after the codes were cleared and plugged in my scan tool I got all codes except P0606, it came back after I started the car until it died

My OBD scanner has some digital gauges on it, the throttle one shows 99 out of 100 (it was a snapshot so I don't know if it would've varied), Air flow showed 2 out of 40, intake manifold pressure showed 22.5 out of 25

Under the snapshot text readout it shows....

Intake Manifold absolute pressure (InHg) 29.31
Engine RPM 0
Spark advance 61 degrees
IAT 84.2 degrees F
Mass airflow sensor LB/M 0
Absolute throttle position 0

When I got the car the air filter and duct from the airbox to the front was missing so I thought maybe something got in the maf, I took it out and it looked perfect. I carefully cleaned it anyways, no difference

With the air duct removed when you start the engine I can see the large metal circle in the throttle body where the large air duct attaches open slightly but it doesn't move at all when I push the gas pedal in and out. If I slide my screwdriver in there to hold it open more the car actually runs almost smooth and is at about 3300rpm, while it's like that it does rev a little higher when I push the gas pedal and back down when I left off but maybe only a 500rpm difference. I reached my finger in there and opened and closed the large metal circle at the beginning of the thottle body (Sorry I don't know the name) the rpms would vary a few thousand rpms but it would bog down really bad when it was open a lot which I would expect with the air duct off and the maf laying loose, etc.. I've tried unplugging the maf, iat, etc one at a time and notice no difference. I am guessing something is shorted or low resistance on that 5v line that all of those sensors are on or maybe my PCM is shot, has anyone ran across this before and have any ideas of what else I can check? Maybe a copy of the schematic for that line that all of those sensors are off of or a pinout of the pcm so I can see if the 5v is low? Any help would be appreciated.

Thanks in advance,
Mike
 

·
Moderator
Joined
·
2,869 Posts
Thanks for that code list, I’ll do some digging through the FSM, it’s available for free on Tearstone btw if u wanna look yourself

1st of all, be very careful about sticking your fingers inside the throttle plate, those things have enough torque to chop your finger off

2. U bought the car with most of the intake already missing? So someone sold it knowing it had these problems?

Just wanna say right away that a P0606 could be related to a failing engine computer, which could be causing all of the other issues

P0606 and P0642 in the FSM have causes listed as a failed PCM/ECU unfortunately

My guess is that for some reason, the throttle voltage signal circuit inside the PCM/ECU blew up, could’ve been a fluke, could’ve been user error or messed up or shorted out wiring by the previous owner or mechanic messing around with live wiring, idk

So just to clarify, u bought this car and it already had this issues? I hope u got a good deal on it as a mechanics special

I also want to point out that PCM/ECU failure on these cars is extremely uncommon, which leads me to believe that someone working on the car goofed something up by crossing some throttle wires with the power still connected and possibly the key on as well

Do the tests listed in the FSM for the throttle position sensor codes, testing the throttle position sensor Ohms readings to see if they’re good and change according to pedal movement

Pray that it’s just a bad throttle sensor and not your PCM/ECU

Is your car an auto or manual trans?
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #4 ·
Thanks for replying. The car ran fine for 6 months after I got it. I put an air filter in it as soon as I noticed it missing. It's an automatic transmission. I'll look up the service manual. Thx for the advice
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #5 ·
I can get a used pcm on ebay for $40 shipped but I'm guessing I will have to initialize it then program the transponder for it. Does anyone know if that can be done with a SnapOn Solus? I can borrow one from a friend if so
 

·
Moderator
Joined
·
2,869 Posts
I can get a used pcm on ebay for $40 shipped but I'm guessing I will have to initialize it then program the transponder for it. Does anyone know if that can be done with a SnapOn Solus? I can borrow one from a friend if so
1. It has to be for the exact same year as your car
2. It has to be for an automatic, u can’t use a manual one since your car is automatic
3. The VIN number will need to be reprogrammed into it with your VIN
4. The immobilizer system code will need to be resynchronized or defeated with other methods
5. Your keys will need to be reprogrammed to the immobilizer or defeated with said other methods

I’m not sure what the SnapOn can do for this car, but this might be something a dealer with an MUT3 will need to do for u, but, they will refuse to use a junkyard engine, and will require you to buy a brand new PCM
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #7 ·
I finally got a free day to work on this thing. I ended up buying the service manual online because the one at tearstone was missing most of section 13a.
I checked the throttle actuator motor for continuity between pins 1 and 2 and it's good. I unhooked the 2 wires going to it and checked for voltage with the car running and there was no voltage even when you press the accelerator pedal. Then while leaving those wires unhooked I hooked 12volts to those pins and the car revved up like it should, of course it hit the rev limited because I put a full 12volts on there but it didn't sound like it was misfiring or anything like that as it revved up. So I'm not getting voltage to it from the pcm. The P0642 code is for no voltage to the throttle position sensor so I'm trying to trace that down but I can't find the pinout for the tps (The one mounted to the back of the accelerator pedal) anywhere in the service manual. Does anyone know where I can find a pinout for the pcm so I can see if a voltage going into it is missing and see if the voltage for the tps is present at the ecrm (Maybe I have a broken wire between the pcm and tps?)

Thanks,
Mike
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #8 ·
UPDATE- The car now runs perfectly fine but the 2 small ground wires that attach to the chassis between the pcm and fusebox are getting super hot. I had removed the pcm and put it back in to look for corrosion in any of the plugs going to it. When I put it back in the car started and ran but a little smoke came from the area near that ground wire so I took the ground off, cleaned the terminal til it shined, scraped the paint off to bare clean metal underneath and put it back on. It gets hot in a matter of seconds. I'm assuming there is a dead short somewhere. Now I just have to track it down.
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #9 ·
Running a 4 gauge ground from the negative battery terminal to the engine block and replacing the terminal on the small ground wires next to the fuse box under the hood fixed it. Runs fine, no codes, small ground wires no longer get hot and smoke. Thanks for all the help.
 

·
Registered
Joined
·
44 Posts
Im having issues with a P2138 code . Can you tell me exactally where ( maybe a picture ) of the grounds you fixed ? This is driving me nuts . Thanks For Any Help You Can Provide !
 
1 - 11 of 11 Posts
Top