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C1256 My findings
- Thread starter FXR UPR
- Start date
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- #2
Our 99 100 had an abs issue while my wife was driving to work. She said the lights in the dash lit up and a loud beeping started. This was accompanied buy a very soft brake pedal and lack of stopping when the brakes were applied. I was able to get the truck into the shop and found I had code c1256 accumulator low pressure malfunction. I tracked down the issue to the motor on the accumulator. I could tap the motor and it would start working again. I was able to order a new motor/accumulator assembly. Sorry I didn't take pics of the procedure but I removed the entire master cylinder/accumulator assembly. I removed the old accumulator and motor assembly and reinstalled the new one. Bled the brakes and we were back in business. I wanted to see whet the issue was with the old assembly. I suspected the motor had failed. I was correct. Once disassembled I found the copper segments that the brushed ride on had worn to the point of delaminating from the rotor causing loss of contact and no accumulator pressure for the brakes.
Interesting. The commutator looks badly worn [the segments that had not delaminated], which is no surprise for a '99 with high mileage.
How many miles on it? Mines rapidly approaching 250k and it might be a good idea to find a replacement ABS pump motor for the inevitable day when the original quits.
How many miles on it? Mines rapidly approaching 250k and it might be a good idea to find a replacement ABS pump motor for the inevitable day when the original quits.
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- #4
215000 miles. There is still quite a bit of the brushed left. One I get some extra time Im going to see if it can be repaired by an electric motor shop.
If the motor can be rebuilt pls let me know. Might have to buy it from you as a safety spare.
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- #6
I would be nice to be able to but just the motor instead of the accumulator with the motor. I work at a lexus dealership and my cost was close to $2000.
That's why I'd like to buy your motor if it is rebuildable 
Thanks for tearing it down and sharing your findings! Did you buy just the motor accumulator, I thought it came as a full master cylinder assembly?
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- #9
I was able to buy the accumulator and motor as 1 unit. The master would gave been another $2000 more. These things are expensive
sent with smoke signals
sent with smoke signals
- Thread starter
- #10
Part number for accumulator/ motor assembly is 47070-60010 fir my 99
sent with smoke signals
sent with smoke signals
I just got diagnosed with the dreaded C1256 and had the same symptoms, ABS/Brake Lights on and Warning buzzer…
did you have to pull the master cylinder to do the Accumulator replacement? My local (non-dealer shop) said I'd have to take it to the Dealer since it would likely have to be a reprogram and SST-bleed job.
I've had the two-pump pedal issue for the last couple of months, which I thought was related to the pedal plunger seals many mudders have had here on their 100s
did you have to pull the master cylinder to do the Accumulator replacement? My local (non-dealer shop) said I'd have to take it to the Dealer since it would likely have to be a reprogram and SST-bleed job.
I've had the two-pump pedal issue for the last couple of months, which I thought was related to the pedal plunger seals many mudders have had here on their 100s