Hydraulic pump relay issue (1 Viewer)

[Khoa]

Hi experts, my LC200 (2002) has the main brake light warning lit on together with the ABS warning light. I have scanned check and it said somethings about the hydraulic pump relay problem, does anyone having the same issue and know where is the location of the hydraulic pump?

 

[2001LC]

Booster hydraulic pump & motor. Are located on the bottom of brake master!

1. Does brake pedal feel normal.
2. Are brakes functioning normal.
3. Check fluid level. By first evacuating accumulator. The instruction are printed on the brake fluid reservoir.
4. After evacuating accumulator. Then turn key to on (do not start), and time how long booster motor runs. You should be able to hear the motor run and see fluid level drop (filling accumulator) at this point. Spec is 30 to 40 second run time, after evacuation. Note: battery should be over 12.5 volts during run time tests. The lower the battery the long the test run time results. If you've had low voltage due to dead or low battery, it can set off ABS/brake lights on dash.
5. Repeat 5 times. Run time should be the same each test.
6. Clear codes and see if they come back.

If you do not have good mechanical skills. Take to a competent mechanic. Loss of brake pressure will cause brake failure.

Poll on total brake failure in 100 series

There is some discussion going on of total and sudden braking failure in 100 series models, with reports of no -or essentially no- braking left at all a very short time (of the order of seconds/minutes) after dashboard warnings. That is scary stuff. It is, however, also difficult to find out...

forum.ih8mud.com

 

[Khoa]

Booster hydraulic pump & motor. Are located on the bottom of brake master!

1. Does brake pedal feel normal.
2. Are brakes functioning normal.
3. Check fluid level. By first evacuating accumulator. The instruction are printed on the brake fluid reservoir.
4. After evacuating accumulator. Then turn key to on (do not start), and time how long booster motor runs. You should be able to hear the motor run and see fluid level drop (filling accumulator) at this point. Spec is 30 to 40 second run time, after evacuation. Note: battery should be over 12.5 volts during run time tests. The lower the battery the long the test run time results. If you've had low voltage due to dead or low battery, it can set off ABS/brake lights on dash.
5. Repeat 5 times. Run time should be the same each test.
6. Clear codes and see if they come back.

If you do not have good mechanical skills. Take to a competent mechanic. Loss of brake pressure will cause brake failure.

Poll on total brake failure in 100 series

There is some discussion going on of total and sudden braking failure in 100 series models, with reports of no -or essentially no- braking left at all a very short time (of the order of seconds/minutes) after dashboard warnings. That is scary stuff. It is, however, also difficult to find out...

forum.ih8mud.com

View attachment 2652524

Thanks 2001 LC, the brake function is ok, I have the vehicle brake inspection on the rollers and all everything is okey, the pedal feel good and smooth. I will go through your 6 steps advice then see if it works. Cheers

 

[Khoa]

Thanks 2001 LC, the brake function is ok, I have the vehicle brake inspection on the rollers and all everything is okey, the pedal feel good and smooth. I will go through your 6 steps advice then see if it works. Cheers

I just have gone through 6 steps for releasing the pressure on the accumulator, I just took 27-30 brake pumps to feel no resistant on the brake pedal. When I turned the key back on, it took 31-33s for the hydraulic pump to run, but the weird thing was that, it interrupted at after about 5s then continue running again until the accumulator "thinks" it's enough pressure. When I clear the faulty reading, the ABS light went off but the main brake light still remains lit on . and it still says the hydraulic relay problem? Does that mean the motor is tired? or just the relay which I still don't know where is located? (my previous question I meant to ask the location of the Relay, not the pump, sorry )

 

[Khoa]

Problem solved: ABS MRT2 relay was broken

 

[2001LC]

Great, glad you solved it. BTW: It normal for the pause during booster motor run time test. Your test results sound fine. Pedal pumps on high side, but normal with age. It's when I see 35 to 40 pumps of pedal, I start to become concerned about accumulator.

 

[Khoa]

Great, glad you solved it. BTW: It normal for the pause during booster motor run time test. Your test results sound fine. Pedal pumps on high side, but normal with age. It's when I see 35 to 40 pumps of pedal, I start to become concerned about accumulator.

Thanks alot, Im very glad that you take time to give a great advice, it helped me to solve problem, have nice day