DialedLife

So my car has the check engine light on, so I scanned it. Engine coolant temperature sensor. So I replaced it and reset my ECU numerous times and its still there.

Took it to the shop and they checked it out for me, since I've been told they can fix anything and all they told me was that: its a wiring problem. They checked and couldnt find where it was.

So, I was wondering if this is a common problem? If it messes up in a specific area? Or do I just have to test it all over the place untill I find it?

thanks in advance for any help.

Former User

Assuming that the replacement ECT sensor is good (some car parts are bad right out of the box), then there could be a bad wire or a bad ECU. The ECT sensor has 2 wires - power and ground. Testing the power wire for 5 reference volts and the ground wire for a short or open is a simple task.

Dontoh

i THINK i may have had the same problem, if not just disregard this, but you might have the wrong wires plugged into your sensor.. make sure its the right plug

DialedLife

Alright, thats exactly what I'll do then. Thank you for your input !


You mean I plugged it into the wrong spot? Thats not it, I took the old one out and screwed/plugged the new one in right after

Dontoh

no, not plugged into the wrong spot, but the wrong pigtail coming from the harness, im not sure if we're talking about the same thing, but i think they can be mixed up with another plug.. thats the problem i had anyway

Former User

If you want the OP to check whether the correct connector is plugged into the ECT sensor (2-wire sensor below the distributor), then tell him the wire colors in the connector that match with the sensor. In this case, the ECT sensor connector should have a Red/Wht wire (power) and a Grn/Blk wire (ground).

Dontoh

yeah ron, just had no clue, figured i'd toss in 2 cents and hope for the best lol..

op here is the problem i had, not THAT informative, but it may help
https://honda-tech.com/forums/showth...2968262&page=2

DialedLife

Tthat's how I guessed it.


Here's what we did today on the issue.

We checked the wires by the sensor to see if it was getting juice. No juice.
Checked them by the ECU, no juice.
So we unplugged the harness at the ECU, and forced juice into it, then tested the wire. The wire got juice.

So.. This would mean the ECU is bad right? If that is the problem; what ECU do I buy?

Also by the ECU, the wires had been cut/worked on before.

Former User

If you unplug the ECU connector and test for voltage at the ECU pin itself (corresponding to Red/Wht wire terminal), do you now measure about 5 volts? If not, replace the ECU and either fix the cut wires properly or replace the cut wire harness.

DialedLife

We don't have an ohm meter. We were using a fuse tester.
We were using the battery charger to put power through the pin.

The power went through to the wire fine. Alright, ECU it is. What is the ECU called? Aren't they something like p046 (random guess)

Former User

Would your tester register 5V?

Never test any ECU circuit with an analog volt tester. It risks destroying sensitive components. You can buy a digital multimeter for $3-$25. Shop around and check for a sale at Harbor Freight Tools. Get one and do the tests correctly before you buy an ECU.

DialedLife

Yeah we tested it directly and it lit up. Alright I definitely won't do that again. I'll go buy one and test it again.

Thanks a lot for your help Ron and Dontoh! Trying to get this thing to pass DEQ and register it so they'll drop these tickets.

DialedLife

So heres what happened today.

Bought a new ECU, garenteed to work. Plug it in, CHECK ENGINE LIGHT IS OFF ! But the car won't start?

Weird. So I plug in the old ECU. Check engine light is still off, and the car runs great.

Wiggle the wires around by the ECU and it starts idling funny, then the check engine light turns on.

Why is that?

Would these mean the 'new' ecu is bad ?

Dontoh

or your ecu pigtails/wiring