Thread: Ecu codes

I just bought a 2001 GTP off a guy for 2,400. At the time of purchase I did not notice anything to strange with the car. So I took my car to Pep Boys to have my codes ran from a CEL. These are the codes I am getting.

PO128:Coolant temp is low
explanation- power train control module verifies that the engine is at a proper temperature.
Probable cause- Check coolant level
Thermostat defective
ECI (engine coolant temperature) sensor
(To fix this issue I am going to buy a radiator and ECI sensor. I have already gotten a new thermostat)

P0304:Cylinder misifire detected-cylinder number 4
explanation- Power control module monitors the crankshaft spped and has detected a misfire condition.
Probable cause- Ignition system fault-spark plugs, ignition wire, coil.( to fix this I got new spark plugs)
Vacuum Leak(not sure what to do if this is problem)
High or low fuel pressure(not sure how to check this if its the problem)

P0742: TCC stuck on
explanation- TCC command off by the ECM- TCC slip detected after off command
Open or short circuit condition
Blocked passage in transmission
Check transmission range switch for proper operation
I am going to try and see if cant clean the sensor. I am thinking that it is dirty. I read some where on line to clean the sensor with windex
or a none grease product.

PO420: Catalyst efficiency low-bank 1
explanation- The oxygen sensors monitors the Catalytic Converters ability to store oxygen.
probable cause Catalytic convertor defective ( failure possible due to #2,3,or 4) <-----are the referring to the spark plugs
large vacuum leak <------ the guy before put a after intake on it. the bung is not all the way in the tube. when i call the company
that makes the intake they said did make one for that model year. Sprectre is the company,
Engine oil leakage into exhaust value guide seal, piston rings<-------this one worries the most about the car. I hope nothing is wrong on the inside

So really I could take it to a shop and find out exactly what is going on instead of guessing,. the reason for the post is I want to see if these are common problems people have with this car. if anyone has any insight that would be awesome. I just hope I did not get ripped off. I usually do not buy used cars private party.

Originally Posted by Explicit_Spade

You paid 2400 for it? I hope its low mileage...

Why are you replacing your radiator for a low coolant code? Seems like the last step... You should try to get air out of the system first...

Missfire... Change your plugs and wires, if the issue continues, move coil packs around and see if the miss follows the pack.

Change, don't flush your trans fluid and filter.

Does your car have a cat? If not you will throw this code.

You say you think you have a vac leak, you should check it with starter fluid. Idle the car, go under the hood and spray around all the gaskets and vac hoses. Well what would you consider low miles its has 156xxx most of the GTP here in Cali are around 3500 with the same amount of miles.

Get rid of the spectre intake. They are garbage.

Well I live in Cali so there should be a cat on there. I can double check tomorrow. As far as replacing the radiator it has a leak and do not want to fix it with STOP LEAk. I really want to get rid of that intake anyway I am going to get a stock one from someone off this site. I will be sure to get some starter fluid and check that out.

I just went to a mechanic today and gave him the list of codes my car was throwing. Him and another guy there where saying the car has majors issues and to diagnose the issue would cost around 170 or so. My brother who is ASE cert and a gear nut told me that it is a good car and just needs a few things fixed. i know this shop was thinking with the best initiation but I do believe they really wanted my money. I called Meineke and they told me $90 bucks to look at it and that would go towards the repairs. So i do not get why that other shop was so high priced.

Originally Posted by BillBoost37

Because Meineke will take three times as long and use cheaper parts. Therefore they'll make up money on fixing it for you. The mechanic is being reasonable with about an hour or two diagnosis time.

Low coolant temp. This can be a thermostat or coolant temp sensor typically. Although it might be wiring etc. Typically it's a $30 or less cost for parts and 30 minutes of labor. It should be diagnosed with a scan tool to ensure the temp on the dash and pcm are low or different from each other. There are technically two sensors built into the coolant sensor. One for the pcm and one of the dash.

Misfire: car probably needs a set of wires and plugs. Under $100 in parts and about an hour of labor

Catalyst: you likely need a new cat. Yours is not meeting the O2 sensors expectations. Your in Cali.. Say 1 hour to weld it in and the cost of the cat, which can be pricy.

TCC: this is the big one in my book. Needs to be diagnosed with a scan tool and if it exists, this can be a solenoid, sloppy valve in the valve body etc. Say an hour to diagnose and then potentially an expensive repair.

Yeah I have been reading about TCC thing sounds expensive. Why not just buy a used tranny at this point. I guess best bet is to let them run there test. As for the low coolant temp they guy put stop leak in the system. I guessing that is why the system is saying low coolant. The thermostat does not work either. I'm guessing that sensor is blocked.So I have the parts to fix this issue. I was thinking about getting a new radiator.

So if anyone is reading this I got the car back from the mechanic. I need to replace the intake and exhaust gasket, they found leaks. Driving it home it starting smoking a bit. From what I can see it was oil leaking onto the exhaust manifold. Was kind of scared it was going to catch fire. They replaced the Cat for me. There are a few bad sensors Intake air temp, coolant thermostat. There is something still going on with the tranny. PO742 and PO730. So I got quite a bit of work to get her going. Just makes me sort of mad the guy did not tell me what was up with the car. At the same time I should have gotten those check engine light sh*t check out before I got her.