New ABS problem
01-11-2017, 05:15 PM
#1
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Model: Cherokee
New ABS problem
1999 Grand Cherokee 6 cyl. 2WD.. I've read a lot of posts here, was on YouTube, and read on line discussions and none really addressed the problem so I thought I'd try here.
A couple of weeks ago I started the car and after the warning lights went out I got a tone and the ABS warning came on. It came on before the car moved. At start all the warning lights came on then went off. About 5 seconds later, with the car not moving, there was the warning tone and the ABS light came on.
There is plenty of brake fluid, the sensors are clean, fuses are good and the brakes work fine. I get no code from the trip odometer or from an old OBD II meter. I've been told if I want to find out why the light is on I'll have to go to a dealer.
Anyone have this problem...or know how to take care of it?
A couple of weeks ago I started the car and after the warning lights went out I got a tone and the ABS warning came on. It came on before the car moved. At start all the warning lights came on then went off. About 5 seconds later, with the car not moving, there was the warning tone and the ABS light came on.
There is plenty of brake fluid, the sensors are clean, fuses are good and the brakes work fine. I get no code from the trip odometer or from an old OBD II meter. I've been told if I want to find out why the light is on I'll have to go to a dealer.
Anyone have this problem...or know how to take care of it?
01-11-2017, 08:53 PM
#2
Old fart with a wrench
You don't need to go to a dealer, but to someone who has a DRBIII scan tool.
The PCM makes diagnostic scans of all systems at intervals and if a problem is found, will set a light. The ABS system is a separate system in itself so it has it's own trouble light. It is not connected to the primary data bus for the rest of the jeep. I've been sitting idling for over an hour and heard the tone and had the light come on. My mechanic friend used his DRB scan tool and said 3 of the 4 wheel sensors weren't responding, so I replaced all 4 at a cost of about $200 only to have the scan tool tell me there was an open circuit to the ABS pump! I said "Screw it!" I'm not paying $350 for a pump module and possibly $325 for a control unit to have the ABS system work! NY State doesn't require it to work and I'd rather not have it anyway! I've been driving for over 55 years using my foot as a brake control and haven't crashed yet because of locked up brakes.
I pulled the fuses and got weird VIC messages that had nothing to do with the ABS system, so I put them back in and put a piece of black electrical tape over the light. If you take the bulb out, it has a backup. The red "brake" warning light comes on that normally only tells you if the e-brake is set or you're low on brake fluid.
There are a couple of things you can check. Check all 4 wheel sensors for damaged wiring or bent,broken mounting brackets, and clean the tone rings. They are on the drive axle CV joint just behind the hub mounting plate. They look like a gear with the teeth cut off. The wheel sensors hang over them and "read" the notches to determine wheel speed. The rear ones are inside the e-brake drum.
My 97 ZJ only had 2 wheel ABS and I never had a problem with it. In 99, they went to 4 wheel sensing, thus the problems began. On the 2004 and newer jeeps, the sensors are used to help control the LSD differentials in the Quadradrive system by reading wheel speeds and activating the lock-up feature.
The PCM makes diagnostic scans of all systems at intervals and if a problem is found, will set a light. The ABS system is a separate system in itself so it has it's own trouble light. It is not connected to the primary data bus for the rest of the jeep. I've been sitting idling for over an hour and heard the tone and had the light come on. My mechanic friend used his DRB scan tool and said 3 of the 4 wheel sensors weren't responding, so I replaced all 4 at a cost of about $200 only to have the scan tool tell me there was an open circuit to the ABS pump! I said "Screw it!" I'm not paying $350 for a pump module and possibly $325 for a control unit to have the ABS system work! NY State doesn't require it to work and I'd rather not have it anyway! I've been driving for over 55 years using my foot as a brake control and haven't crashed yet because of locked up brakes.
I pulled the fuses and got weird VIC messages that had nothing to do with the ABS system, so I put them back in and put a piece of black electrical tape over the light. If you take the bulb out, it has a backup. The red "brake" warning light comes on that normally only tells you if the e-brake is set or you're low on brake fluid.
There are a couple of things you can check. Check all 4 wheel sensors for damaged wiring or bent,broken mounting brackets, and clean the tone rings. They are on the drive axle CV joint just behind the hub mounting plate. They look like a gear with the teeth cut off. The wheel sensors hang over them and "read" the notches to determine wheel speed. The rear ones are inside the e-brake drum.
My 97 ZJ only had 2 wheel ABS and I never had a problem with it. In 99, they went to 4 wheel sensing, thus the problems began. On the 2004 and newer jeeps, the sensors are used to help control the LSD differentials in the Quadradrive system by reading wheel speeds and activating the lock-up feature.
Last edited by dave1123; 01-11-2017 at 08:59 PM.