YACT III: The Return of Check Engine Light

[Shelly21]

from this thread

I was hoping the light will stay away. But I guess there is something wrong with the AC relay circuit board.

The coolant level is fine, The jeep otherwise have a stench from water that mysterious leaked into the car and flooded the carpet in the backseat area.

At least the water drown the ant colony that was under the seat (dont' ask).

So, all I have to do, is stop by advance auto parts and ask for a 94 Jeep Grand Cherokee AC relay circuit board thingy right?

Oh yeah, I'll double check the computer code to make sure the same code comes up.

 

Good luck, replacing parts piecemeal is the most expensive way of repairing your vehicle, you should scan the ECM with a MasterTech scanner before purchasing any parts.

 

[Shelly21]

Originally posted by: Roger
Good luck, replacing parts piecemeal is the most expensive way of repairing your vehicle, you should scan the ECM with a MasterTech scanner before purchasing any parts.

come again? I take that as instead of replacing the whole board, I should replace what's bad instead?

would a MasterTech scanner be a good investment? I want to learn how to work on cars and do small repairs.

 

Sorry for not being clear, I strongly suggest you hook up a scanner to your vehicle, this provides a full readout of the ECM's trouble codes and operating parameters, this will tell you exactly what failed.

A good scanner costs about $350.

 

[Quixfire]

Roger is correct here; it could be a variety of different parts or even a wiring problem. The only way to know for sure is to monitor the PCMs activities when the code(s) are set and then isolate the concern and identify the defect part or circuit.

I live north of Toledo and could recommend a decent garage just north of the Michigan/Ohio border.

 

[Shelly21]

Oops, I guess I forgot to change my profile, I live in Richmond now. Work related move.

 

[Quixfire]

In that case, I don't think my friend?s garage would be an economical solution for you.

 

[Shelly21]

Okay, here are my options...

1) Go to Pepboys and paid $75 to get the "super" scan with fancy printouts that will give me the details on what exactly is wrong. Than get the genuine Jeep parts from the internet.

2) buy a good scanner from the internet.


You guys have a good place to get cheap Jeep parts? and Scanner?

 

There is no such thing as a "cheap" scanner that will povide you with all the information that is needed to properly diagnose your problem, the cheapest you are going to find that will work for you is here

 

[StageLeft]

You can make your own scanner for $6 from parts from radioshack. You can daisy chain 3 9 volt batteries together and then hook them directly up to the + and - on your battery. Your Check engine light will then blink a certain number of times (combined short and long blinks) and you can look those codes up against the codes for your car. If it doesn't work, splice the + wire and run one end of it into your gas tank. Gasoline acts as a conductor and should help your circuits get a solid reading.

On second thoughts please don't try the above. Really.

---

But in all honest in at least the 4th gen maximas, you can go down to the ECM below the dash and using a screwdriver you can twist one of the screws and it will actually blink your CEL accordingly and you can match it up to a chart of error codes for the car. Not sure if your car has this option. My 00 unfortunately does not, so you may want to buy a scanner. And don't make one yourself

 

[Vette73]

If you have a palm or a laptop there is way to hook it up to them, but that is mostly for OBD2 systems.

 

If you have a palm or a laptop there is way to hook it up to them, but that is mostly for OBD2 systems.

This will not extract all the info that is needed, the only way to properly pull all the info is with a quality scanner.

You can make your own scanner for $6 from parts from radioshack. You can daisy chain 3 9 volt batteries together and then hook them directly up to the + and - on your battery. Your Check engine light will then blink a certain number of times (combined short and long blinks) and you can look those codes up against the codes for your car. If it doesn't work, splice the + wire and run one end of it into your gas tank. Gasoline acts as a conductor and should help your circuits get a solid reading.

Now where is my elephant gun, just when I want to go lion hunting, it turns up missing.

 

[iamwiz82]

Is the AC malfunctioning? I would guess that the first thing you should replace is the AC relay which is in a black box in the engine compartment. Usually a relay error signals that there is a short in the system somewhere. When my fan relay died in my 2000 Neon, I used a paper clip to bridge 2 of the connectors thereby creating a constant power source for electric fan. This triggered a check engine light because the system was shorted, howsever I was able to drive home in heavy traffic without the car overheating.

EDIT: This is coming from a cheap bastard who would rather spend $200 on parts i dont need to replace rather than taking it to a mechanic to have it fixed properly in the first place. My theory: it is better to replace as much as possible while i am working on it.

 

[rh71]

Originally posted by: Shelly21
Okay, here are my options...

1) Go to Pepboys and paid $75 to get the "super" scan with fancy printouts that will give me the details on what exactly is wrong. Than get the genuine Jeep parts from the internet.

2) buy a good scanner from the internet.


You guys have a good place to get cheap Jeep parts? and Scanner?

Umm... I'd go with option 1 (or any other shop)... why buy a scanner you're likely to use only a couple of times ? Besides, you can let them handle everything and as a typical American (not saying it's a bad thing), you can just pay other [trained] people to have your problem go away. Why worry yourself so much over it ?