Honda Car Forum

I bought the car with ABS faulty code. Honda service history has a note saying Left rear ABS sensor faulty needs replacement. Upon trouble shooting abs fault code its 1.3 = ABS motor relay/ circuit problem. I did a flow chart (some honda manual found online) to diagnose this and they ask me to take out my ABS motor relay (tested OK) and jumper two wires. It then asks if my pump motor runs but then it does not, so the flowchart continues and everything checks out OK ending on check any loose control unit connections which i did, no luck.How would i know if the Pump motor is running? and does the ignition have to be on or does the car even have to be started? Ps i have hayes and online pdf manual so simple stuff i know like resettting trouble codes checking them ect...now the faulty Sensor diagnosed by HONDA.Using my digital multimeter I compared the resistance on the 2 back sensors aswell as with a spare sensor bought from ebay. And the left rear one indicates 5.x (x counts up or down) the others shows 0.84. So it does look like its faulty but i played on...unplugged the 2 rear sensors and cheking the volt :+ on sensor wire and - on common ground (car metal spot)and then turning the wheels....strange i got no voltage at all stays on 0.000. on both rear sensors... Did the same with my spare sensor while holding it near the pulser ring and turning the wheel(hub actually) ... i got between .4 and .9 reading. so I thought doulbe check it with one of the front sensors...connecetd it up and turned the wheel....0 voltage.I dont know whats going on...acording to the resistance reading the left rear sensor shows different reading from everyone else. But from voltage point. only the spare one gives me a reading, non from car does. ???Im doing major suspension replacement on the car so it cant move...I have wired the spare sensor up without installing it and checked to see if fault code goes away after clearing it, and it does not. Do i need to get all 4 wheels turning before abs control unit finally clears fault and turn light off?

Some cars have an ABS control box located on or near the master cylinder under the hood. The connectors may be loose or the controller may be faulty. Also check sensors at the disk.

The step where you jumpered the wires is when the pump should run because you are supplying power to it and bypassing all of the controls. If not, then you want to check the power supply to the motor as well as the ground circuit, and if these are both good then the motor needs to be replaced. If you have good ground but no power then start with fuses then move on to additional components, start with the ones on the wiring diagram that are the easiest to access and divide and conquer until you find it. If it has good power but no ground then you need to go backwards from the negative terminal and trace to where there the ground disappears. The speed sensor with a different ohm reading is probably faulty, but ohm resistance tests can be misleading, although the other three are very close to each other and there is precedent that this needs to be replaced. I think that the reason you get no reading for the sensors is that you have one probe on the sensor wire and then one on the body ground. Since there is no connection between the two when the connector is unplugged, you're not going to register a voltage difference at any level. Try putting the positive probe on the sensor wire and the negative probe on the other terminal at the connector and I think that you'll get a signal from at least three of them. You're probably already doing this with the spare sensor and this is why you're getting a voltage. I do recommend having the ignition on to check for whether or not the pump motor runs because it may not if it is on a circuit that is only hot in run. You can tell by looking at the wiring diagram, which will state whether or not the circuit is hot all of the time, or only in start and run. It sounds likely that you will need a new pump motor as well as a left rear speed sensor. The motor is probably only sold as a complete hydraulic modulator assembly. Hope this helps.

Problem one- If there is a fault code set and the ABS light is on, the system is disabled untill you clear the code in the computer. You never indicated that you did this.Your pump running should be audible in all but the most intense garage band moments.Higher resistance is a cause for rejection of a sensor, but the only tue test is to use an osciliscope and check the wave form generated by the assembly in motion. Yeah who has one of those.Ever check power to the motor after bypassing the relay???? Ever check power to the pins you bridge when bypassing the relay???Keep pluggin, I know you're stuck in the garage.By the way she will have working brakes, just no anti-lock function with this problem.ASE Cert. Auto tech, Worked 20 years on aircraft ABS(Anti-skid) too.