C1226 RF Excessive Wheel Speed Variation
Thread Starter
Safety Car
Joined: Dec 1999
Posts: 4,202
Likes: 2
From: Plano TX
C1226 RF Excessive Wheel Speed Variation
Has anyone else had this failure on their Vette?
Car has been in 3 times. Dealer has replaced the hub, connector, & harness on the RF. Failure still occurs, with no discernable pattern, and sets C1226.
Dealer wants to plug in a Tech 2 after failure (before engine shutdown), but of course, it didn't trip in 3 hours of driving (failed multiple times every day since last Tuesday).
I want to know if there is a better way to determine the cause of the failure. Thanks.
Car has been in 3 times. Dealer has replaced the hub, connector, & harness on the RF. Failure still occurs, with no discernable pattern, and sets C1226.
Dealer wants to plug in a Tech 2 after failure (before engine shutdown), but of course, it didn't trip in 3 hours of driving (failed multiple times every day since last Tuesday).
I want to know if there is a better way to determine the cause of the failure. Thanks.
Safety Car
Joined: Aug 2000
Posts: 4,933
Likes: 30
From: San Rafael CA
Re: C1226 RF Excessive Wheel Speed Variation (TooManyIDs)
I also replied under my thread (Stainless Steel brake lines throwing codes) but thought I'd document it here too.
I have the Russell SS braided brake lines, and my car started showing a C1225, which is the same error as you're getting, but for the LF instead of the RF. Dealer says the problem is with the SS brake lines. GM recommends returning to the stock lines. Other forum members seem to indicate that they do not get this problem with other vendor brake lines. According to the Service Manual, a C1225 through C1228 is:
The EBCM detects a rapid variation in the wheel speed. The wheel speed changes by 10 mph or more in 0.01 second. The change must occur 3 times with no more than 0.2 seconds between occurances.
The manual further goes on to say:
A possible cause of this DTC is electrical noise on the wheel speed sensor harness wiring. Electrical noise could result from the wheel speed sensor wires being routed to close to high energy ignition system components, such as spark plug wires.
My dealer says it is a grounding issue, but he isn't clear on whether the brake lines should create a path to ground, or whether they should be insulated from ground. Regardless, he says they've had several cars with this problem, and replacing the SS lines back to stock has made the problem go away.
I have the Russell SS braided brake lines, and my car started showing a C1225, which is the same error as you're getting, but for the LF instead of the RF. Dealer says the problem is with the SS brake lines. GM recommends returning to the stock lines. Other forum members seem to indicate that they do not get this problem with other vendor brake lines. According to the Service Manual, a C1225 through C1228 is:
The EBCM detects a rapid variation in the wheel speed. The wheel speed changes by 10 mph or more in 0.01 second. The change must occur 3 times with no more than 0.2 seconds between occurances.
The manual further goes on to say:
A possible cause of this DTC is electrical noise on the wheel speed sensor harness wiring. Electrical noise could result from the wheel speed sensor wires being routed to close to high energy ignition system components, such as spark plug wires.
My dealer says it is a grounding issue, but he isn't clear on whether the brake lines should create a path to ground, or whether they should be insulated from ground. Regardless, he says they've had several cars with this problem, and replacing the SS lines back to stock has made the problem go away.
Former Vendor
Joined: Apr 2001
Posts: 10,976
Likes: 21
From: FL
St. Jude Donor '13
Re: C1226 RF Excessive Wheel Speed Variation (TooManyIDs)
All the wheel speed sensor harnesses connect to a single connector located to the right of the battery,mounted on the inner fender.I have seen poor contact at these terminals causing speed sensor codes :yesnod:
Thread Starter
Safety Car
Joined: Dec 1999
Posts: 4,202
Likes: 2
From: Plano TX
Re: C1226 RF Excessive Wheel Speed Variation (BlackZ06)
After a year and a half and 10,000 miles, I can't imagine why they would fail now, but had the front Russell SS lines replaced with stock today (rear on order).
Will see if that cures it.
Will see if that cures it.
Heel & Toe
Joined: Dec 2001
Posts: 24
Likes: 0
From: San Diego Ca
Re: C1226 RF Excessive Wheel Speed Variation
C1226 is LF. My '98 drove me crazy with these codes! I got real good at eracing them even on while driving. No pattern! It maby had to do with moisture? It is out of warranty and I never replaced any parts but it went away by itself? I think the sensor generates such a low current, and is transmitted to the computer with unshielded wires, and is just not adequate. I would expect all computer communication would be shielded, especially in a car. :smash: :jester
Thread Starter
Safety Car
Joined: Dec 1999
Posts: 4,202
Likes: 2
From: Plano TX
Re: C1226 RF Excessive Wheel Speed Variation (Ddaanc5)
The list used to say LF (Troy fixed CF, Registry will need to update - informed HH), but notice how they are out of sequence around those code numbers.
It's actually RF. Dealer replaced the hub (not cheap) and connector.
It's actually RF. Dealer replaced the hub (not cheap) and connector.
