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Re: ABS - now my pump keeps running when the engine's off Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Thu, 11 May 2006 11:05:19
In Reply to: ABS - now my pump keeps running when the engine's off, Eiron, Thu, 11 May 2006 10:12:58 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Two things come to mind-
First, the relay contacts are sticking together. Cleaning the actual contacts inside the relay should have helped. However, if the plating has been burned off the contacts enough, just a few actuations of the base metal could cause the contacts to fuse together. I'd measure the resistance between pins 30 and 87 on the relay, while it's still out. If you get continuity, the relay is shot. Those contacts should be open with the relay de-energized. The power side of that relay goes directly to the battery, and is not switched. So if the relay sticks, the pump will run even if the ignition switch is off.
The other thought is that the high-pressure switch is bad. That's the 180 bar switch that commands the relay to turn off when the pressure gets high enough. But idea would require at least two things wrong - that's because the power which drives the relay coil is switched through the ignition switch. For the relay to be on with the car off, not only would the 180 bar switch have to be bad, but you'd need to have some sneak path to provide power to the relay coil.
Given the choice of fused relay contacts or a sneak current path turning the relay on, I'll go with fused relay contacts. To be sure, measure the relay contacts with the relay out of the car. TO completely rule out the sneak path, measure the voltage from pin 86 on the relay socket to ground, with the ignition off. It should be 0 volts. If it's 12 volts, there is a sneak path somewhere.
posted by 192.249....
, Thu, 11 May 2006 11:05:19 <-- Viewing This Message, Fri, 12 May 2006 05:05:41
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