red03vet

2003 VET - I've got a thumping noise coming from the left wheel when truning tight left at crawl speed; I'm also showing ABS codes 1221 and 1225 with a new ABS module installed. The codes appeared and then after clearing them a bunch of times disappeared, now have returned. I'm thinking the 1225 code is a result of the 1221 code. I'm thing of replacing the left wheel hub assembly complete with sensor, but the THUMPING noise is throwing me off... Anyone got any ideas or experience with a similer issue? THANKS !!!!

cliff_ford

Before you change the hub check that the female connectors at both ends of the wheel harness are not flattened.

trussme

Wheel Speed Sensors
Codes C1221 thru 1228 indicate that one of the wheel speed sensors is either sending a bad signal or no signal. Start by checking the connections. The wheel speed sensors are integrated into the wheel bearing/hub assembly. The wire coming out of the back is the connection for the wheel speed sensors. Verify that the connector are not broken, damaged, or corroded in any way. Pay particular attention to the female end.

The wire coming out of the wheel speed sensor connects to and 18" jumper harness, then to the main harness. It is very common for people to have a weak female pin in one of those connections. If all of that checks out good, swap the jumper harness from side to side. For example if the left front is bad, swap it over to the right front. And install the good one from the right front to the left side. Then clear the trouble code. If the trouble code is now on the right side, you know the wire harness is the problem. If the code is still on the left side after swapping the jumper harnesses, you know the problem is inside the wheel speed sensors.
If all the wires check out good, it's time to take a trip to Auto Zone for a new set of bearings. You can buy replacement AC Delco bearing from your dealer if you want to, or get the exact same bearing in a different box for half the price (~$150) from Auto Zone, you decide. While you’re at it, this is a good time to upgrade the lug studs and add spindle ducts.

lucky131969

I would at least test the WSS output with a meter.....before buying a new assembly.

1REDZED

Red03,

I just had that same code 1225 come up just over a week ago. In additon to a few others I might add.

I took Bill Curlee's advice in this link:

http://forums.corvetteforum.com/c5-t...tion-long.html

I cleaned all ground points/connectors (male and female ends)at the locations as indicated in the link, and the checked the pigtail connectors at each wheel sensor.

The problems went away. All TC's are off.

The one ground location in the diagram in the link was a bit hard to find, but it was nearly straight down from battery on the frame rail.
I had factory paint/black at the base of many of my contact points.
I used sandpaper to remove some of that black paint to help give things more of a clean grounding surface.

Also I learned it was ill advised to even lightly coat the connector pins with dielectric grease- of couse AFTER I did it. It just may hinder good contact with the pins.

Any how, I hope it works out.

About that "thumping" Let us know what the heck thts all about.