2000 Alero 3.4 ABS light on, code c1265

[skeeter123]

ABS light (and only ABS) on my 2000 Alero recently came on. At first it was intermittent, I checked wires going back ~2 feet from each wheel bearing, they all looked OK; checked/reseated sensor connectors on all hubs. All hub sensors had ~1100-1200 ohm resistance. Front hubs were replaced ~4 months ago. I thought it might be water-related since it seemed to happen after it rained, but now its on constantly. I got an ABS-capable scanner a week ago, got three codes:

C1232 Left front wheel sensor open or short
C1265 Left rear inlet valve solenoid malfunction
C1286 Steering sensor bias malfunction

I cleared all the codes a week ago, only the C1265 comes back. Others never re-appeared though car has been driven daily. Using the scanner, the C1265 code can be cleared, but it comes back immediately. By this I mean that with the key-on, engine-off (and ABS light on), when I clear the code there is an audible click from the ABS module under the battery, the ABS light goes out and immediately comes back on. Same exact thing happens when I do it with key-on, engine-on; and the engine rpm also hiccups a little. I opened the drivers-side wheel-well, took off and re-seated the big connector on the EBCM module, no effect.

Code says left-rear inlet valve, I'd think there'd be four separate valves/solenoids (one for each wheel) but I only see two connectors on the ABS solenoid module (under battery).
Haynes manual doesn't say much about ABS system.

Is there a way to test ABS module to confirm if its good/bad? Any body have any ideas?

[BNaylor]

What scan tool was used. Was this a GM Tech 2?

The EBTCM module is probably bad. Failing ABS initialization.

[skeeter123]

It's a Equus/Innova 3160 (came straight from Santa so I can't knock it).
- Professional OBD2 Generic Scan Tool all 1996 and newer cars, light trucks, and SUVs - Domestic, Asian and European Import
- Diagnoses ABS codes on 1996 and newer GM, Ford and Chrysler vehicles.
- Retrieves OEM Enhanced and Transmission DTCs
- Communicates with all OBD 2 protocols: C.A.N. (Controller Area Network), ISO 9141, J1850PWM, J1850VPW, KWP 2000 ISO 14230-4

When I hook it up, go to retrieve ABS codes, it prompts to select GM cars, then gets the codes. Seems to know what its doing...

Any suggestions? Can/should I ignore the other now-gone codes for Steering Bias and wheel sensor? Any tests (ohm-meter, etc) that I can do myself on ABS system without blowing up entire braking system?

Thanks for your time.....

[BNaylor]

I would disregard the C1286 Steering sensor bias malfunction for now but work with the other two which appear to be valid. Any wheel sensor or ABS malfunction will affect the Magnasteer system circuits. I'd start with the C1286 DTC.

On this DTC the EBTCM module controls the ABS valve solenoids and pump motor. The C1286 DTC will only set when there is a malfunction in the solenoid circuit internal to the EBTCM module. Therefore, no further troubleshooting is necessary so there is a high probability the EBTCM module is bad meaning replacement. Good luck!

[skeeter123]

Thanks, just checked RockAuto- ~$650 for "ABS control module"; assume thats the same as the EBCM/ETCM. may look around ebay & junkyards....

[skeeter123]

Are there any issues such as having to re-learn or re-program the ABS module, system, or any other process I should be aware of before I find/buy a used or remann'd ABS module? Can I just plug in a different one (same p/n) and let it rip?

Update: I've got a line on a similar module, p/n 09356861, removed from a 2000 GrandAm 2.4L. Mine is clearly a 09356871. RockAuto and other sites all list the part for my car as the 09356861 p/n. I cna't find much for a xxx-71. Anyone know the difference? Or if it would work?
Thanks.....

[skeeter123]

I found a used ABS module with the 09356871 p/n for $50.00. During my search, I found what I'd call "rumors" that the 09356871 was for:
2000 Alero GL and GLS; and 2000 Grand Am's w/variable steering (opt NV7)
The 09356861 is apparently for the:
2000 Alero GX; and 2000 Grand Am w/o the variable steering.
When I get it in I'll update how it works. Fingers crossed....

[skeeter123]

Not good news... I put in the used ABS module(EBTCM) p/n 09356871, no change, still got the C1265 code. Further testing:
- I unplugged the left front wheel speed sensor, the C1232 code came up. Plugged it back in, code went away.
- After reading that the ABS system may do certain functions once car goes over 15-20mph, I took it for a drive w/code reader hooked up. If I clear ABS codes while driving the ABS light stays off. When I stop/restart engine, the C1265 code comes back, along with the C1286 code and ABS light on.
- When just clearing ABS code with car stopped, I get one audible click. If I drive the car and then clear codes with engine running, I hear several louder, sharp mechanical-sounding "clangs", with sound spread out under hood, not just from under battery area.
- I tried to look over magnasteer/power steering assembly as best I could; there's signs of a little fluid-leak where the power steering hoses join the metal pipes that connect to the steering assy, but nothing that looks too bad, Power steering fluid is old and brownish, but not low. I'm willing to flush/replace PS fluid, not sure that would solve this prob.

Could something with the power steering be causing the C1265/C1286 codes? Where is the Steering sensor that has a "bias malfunction"? Is it something I could test/measure/replace? Are there certain wires I could check for signal/continuity? Any help would be greatly appreciated....

[skeeter123]

Well, I've learned that my model (2000 Alero GLS 3.4L) doesn't have Magnasteer (no magnets), but it does have the variable-assist power steering, which uses power steering fluid injected at the base of the steering column to vary the amount of "assistance". This is accomplished by varying the PS fluid that flows thru the EVO (electronically variable orifice) valve at the base of the power steering pump. The connector on the power steering pump isn't for a sensor, its for this EVO valve. I am really at the edge of my knowledge and would appreciate any help I can get.....

Thanks