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Issue/ car: 1997 civic lx. Stock
d16y7 with z6 intake manifold. Rebuilt motor and replaced clutch. Speedometer does not work, live data from ecu shows 0? Mph. P0500 is displayed showing vss electrical fault.
In addition to pulling the motor and trans I power washed the trans with the sensor in it. Sensor has been replaced twice with no change in result.
Also dash board was removed and replaced German dash. Possible kink in dash wiring?
Testing:
Pulled back engine harness to check wiring and connectors. Replaced vss connector with no change in result
Tested 12v at blue/white wire to vss plug
tested 5v at black/yellow wire at vss plug
tested ground to black at vss plug
Tested continuity to dash blue/white wire to sensor blue white wire. Continuity good
Tested continuity from ecu plug blue/white wire to sensor blue/white wire. Continuity good
Tested continuity from dash blue/white wire to ecu blue/white wire. No continuity
question
Now I need to know the path of the wire circuit, I know the vss is fed 12v from fuse 15, I believe the path takes it across the dash to the ecu and then to the sensor.
I know the ecu measures resistance between the blue/white and brown yellow to get signal, however there is no description of how to test brown/yel for continuity.
Last edited by chrysler kid; Jan 10, 2019 at 07:17 AM.
I'm going to re-test again tonight to make sure I'm not remembering wrong, but I thought the blue/white was 12v and black yellow was 5v. If those were my results it means I had a wire crossed
While your in there take a can of compressed air to the vss sensor, use electric cleaning solution and apply di-electric grease. Also clean the vss plug too. Another diagram I looked at shows the blu/wht wire going to c103, or c130. Check there too. Above the ecu or might be that brown rectangle connector on the engine harness.
3 sensors. I'll order another, that's the only logical conclusion. The flow chart is not very good for ecu testing. It asks if voltage fluctuates and the both yes and no answers state to replace the ecu
Last edited by chrysler kid; Jan 10, 2019 at 09:06 PM.
Measure ohms of the blue/white wire from C130 inside the car to the sensor plug. Do this (and all ohm tests) with the circuit de-energized, that is the key off and the battery disconnected.
If you find the circuit is broken (it should be near zero ohms), the first place to check is of course the intake manifold bracket, since this is one of the wires affected by the fuse 15 problem.
The sensor puts out pulses while the car is moving. When the wheels are stopped, the output may stop at zero or at 12 volts. The important thing is that it pulses when the wheels are turning. So the test to jack up one wheel, put transmission in neutral and turn the wheel by hand is important.
its only suppose to show voltage when the wheels are spinning
Not trying to trigger you (), but this^ is not how the VSS circuit works.
Originally Posted by chrysler kid
Why the fuc does the plug to the sensor show 5 volts and the plug to the ecu and dash show 12
The ECU and speedometer (also cruise control) separately supply reference voltages (~5V) to the VSS, which in turn grounds the reference voltages at frequencies that correlate to car velocity (mph) at the wheels. The reference voltage (12V) supplied by the ECU is clearly higher than expected. If you depin the VSS wire from the ECU connector to eliminate the ECU reference voltage from the VSS circuit, does the speedometer now work?
Last edited by muellersfan; Jan 11, 2019 at 05:27 AM.
Ah, if going by his OP he has continuity to the cluster but not the ecu. So theres a break probably at c130 as that seems to be where it goes to the ecu correct?
Ah, if going by his OP he has continuity to the cluster but not the ecu. So theres a break probably at c130 as that seems to be where it goes to the ecu correct?
There's not one problem in the circuit. There are many.
Continuity between speedometer and VSS should allow the speedometer to work, so there must be a second problem in the VSS-speedo circuit, possibly the speedometer itself or the VSS. Third and fourth separate problems are in the VSS-ECU circuit, which include abnormally high ECU reference voltage and the lack of VSS-ECU continuity (broken wire or internal C130 junction connector issue). Don't expect the solution of this P0500 issue to be simple.
P0500 vss and no speedo
), but this^ is not how the VSS circuit works.
