ullman

I'm a newbie to this neat forum. I didn't put my Accord year in the title of this post, as I believe the ABS unit is the same across several of the 7th gen Accords.

Anyway, I have a 2003 Accord EX (4cyl) that's been a bit of a lemon. Lots of various problems over the years. The latest is an ABS pump motor relay short (53-1).

I took it to the dealer and they inspected the ABS modulator unit. They said the terminals(?) were corroded and they either cleaned or replaced them before testing it again. The ABS still throws the 53-1 code. They're quoting $1200 to replace the ABS modulator.

There's a Tech advisory (TS021103) which states that the service Manual troubleshooting for DTC 51 and/or 53 prematurely recommends ABS modulator unit replacement. Always inspect and clean the ABS modulator pump motor ground before replacing the ABS modulator unit. It looks like the dealer did this, but didn't check the wires.

My questions:

1. If the ground wire is kaput from the ABS connector to the frame is bad, wouldn't that create a short? Then cleaning the ABS pump motor ground (as the dealer did) will do no good.

2. Is the ABS modulator easily accessible? (I'm not sure where it is, so any help finding it would be great).

3. BillD123 in topic "SOLVED: 2005 Accord Ex: ABS Modulator Failure" tested the wiring in his ABS. He noted: "Found that PINS 24 & 25 had no continuity to chassis ground. Traced wires in harness to ring connector under the power steering Reservoir bracket. Removed, cleaned, reconnected and tested ABS Connector PINS 24 & 25 for continuity to ground. Good ground now present."

If someone has the Factory manual wiring diagram for a 2003 Accord EX, could you check if it's pins 24 & 25 for ground? I'd like to continuity test to ground (I assume one multimeter lead on the pin, one on the frame?), but I need to know which pins to check.

This Japanese fuzzy scanned link indicates that it's pins 24 & 25 (same as BillD123).

Thanks for any help. I can't afford $1200!

justinsbg

24 & 25 are the correct pins to check. Check ground 203 which is on the frame near the power steering reservoir. Take it off and clean it well with some fine grit sand paper. The modulator unit is right beside the windshield washer reservoir. The two ground wires in the 25 pin connector at the mudulator unit are at the end of the connector under a white wire and white/red wire. They are both black wires of course.

ullman

Thanks for your response justinsbg!

Are you suggesting that the ABS Modulator uses ground 203, or just that I should use it to check the pins?

Thanks. Do you know if there is anything else I should check for a ABS modulator relay short (other than the modulator being bad)? Also, if the modulator is indeed bad, roughly speaking, how many hours of labor is required to replace it? The dealer is quoting $300 in labor (in addition to the $160 I already paid to diagnose this). Does that sound fair?

justinsbg

The Modulator uses ground 203. You should be sure that it is clean before proceeding with other diagnostics. If they already charged you $160.00 for a problem they didn't fix, in my opinion they should apply that $160.00 to the modulator repair...if needed.

ullman

justinsbg,

Apparently they did replace ground 203, but they couldn't confirm if they did a pin test. I pulled the connector off, set my multimeter to ohms, and when I checked the four larger connectors (see circled pins in the pic below), they all read 0L with one lead on the pin, and another on the frame. According to my meter, that suggests no continuity = no ground.

It's possible that I did this wrong, in that I tested the cable, rather than the pins in the unit. It seemed to me that the cable was bring the ground to the ABS modulator.

Did I do it wrong-- that is, should I pin test the pins on the ABS modulator itself?

ullman

Well, looks like I can't post a pic, or a link to an imageshack pic. Perhaps if it's posted as text you can copy&paste the link to view it:

imageshack.us/photo/my-images/703/p1040780sm.jpg/

justinsbg

let me take a look at the wiring diagram for your car in a little while. I'm out of town right now. I'll get back with you soon.

justinsbg

With the connector unplugged, put your meter on the ohm setting and put one lead in the connector terminal and the other to ground 203. Do that for each terminal 24 & 25. All your doing is making sure that the wire is not broken or has tons of resistance. One lead on one end of the wire and the other lead on the other end of the wire. You should have little resistance, somewhere around 0.2 ohms. That is checking the continuity of the wire. Make sure that the spot where you place your meter lead is clean. Let me know what you find. It sounds like you're going to need the modulator unit.

soon2bdropped

any update from the OP?

ullman

Pins 24 & 25 aren't marked. I assume it's the bottommost of the 4 larger gauge pins?

I'm not getting any reading, just 0L which indicates infinite resistance. But maybe I'm doing it wrong. When you say "with the connector unplugged,"
you obviously mean the cable. I tested against that cable, not where the cable/connector plugs into the body of the ABS module. See link below:

http://img703.imageshack.us/img703/9823/p1040780sm.jpg

If I look at the parts diagram (see link below) for the ABS Modulator, I don't see any place where a ground comes in, except from the cable/connector.

http://img845.imageshack.us/img845/7...smodulator.png

But do you want me to test what the cable/connector plugs into?

I'm confused.

justinsbg

You're testing the continuity of the ground wires. Both ground wires, pins 24 & 25 of the modulator connector go to ground at G203 which is near the power steering reservoir. So one test lead goes to the pin 24 at the connector and the other test lead goes to
G203. So the wires go from the connector to G203. You are testing that particular pins continuity to ground at G203. If you have little resistance that means you have good continuity to ground. You would do the same for pin 25. I would post pictures but I'm out of town on vacation. It's not likely you're going to find a problem with the continuity of the wires, but it's worth checking. If you would, how about posting pics of G203 and also pics of where you have your meter leads doing the testing so that I can verify you're testing properly.

ullman

Will do-- really appreciate the help. I just started a new job, and have been crazy busy. I'll try tonight/tomorrow.