radiotech

Hello everyone, first post here

I have a 1994 EG hatch with a B20b block, B18c1 head, gsr trans, and p72 ecu. It is throwing a code for a vehicle speed sensor (17) and has the symptoms with a broken speedo/odometer, rough idle, and no VTEC engagement. I replaced the sensor to the letter of a good write up and reset the code on the computer. But a few minutes later the light is back on and the car still isn't running properly. The speedometer rests at about 7 o'clock when the car is off and then spins to rest against the peg (but on the wrong side, 360° from 0mph) when it is on moving.

I've tried searching but I cant seem to find much support for troubleshooting this cel or sensor further after replacment, since it seems replacement is normally the solution. Can someone tell me how to proceed or where to go with troubleshooting?

tech8

First check the connector to the VSS for corrosion on the terminals, damage to wiring, etc.

You'll need a multi-meter for testing.

Unplug the VSS connector.
VSS Terminal no. 1 (Blk wire) is the ground wire from Ground G101.
VSS Terminal no. 2 (Yel/Blk wire) is power when the ignition switch is in the ON or START position.
VSS Terminal no. 3 (Orn wire) is the VSS output which goes to the ECU, cruise control unit, and the gauge assembly.

1. With the multi-meter set to the voltage setting, measure the voltage at terminal no. 2 (Yel/Blk wire) with the ignition switch in the ON position (car is not started or running).
Multi-meter red lead touching terminal no. 2 and multi-meter black lead to body chassis ground (car's bare metal or a ground bolt).

There should be battery voltage on terminal no. 2 (standard battery voltage is 12 volts).

2. If there is battery voltage in step no. 1, do the same test to measure voltage at terminal no. 2; but, this time touch the multi-meter black lead to terminal no. 1 (blk wire). Is there battery voltage?

This test is to check for ground coming through terminal no. 1.

3. With the multi-meter set to the voltage setting, measure the voltage at terminal no. 3 (Orn wire) with the ignition switch in the ON position (car is not started or running).

There should be no voltage on terminal no. 3 with the VSS disconnected. If there is voltage on terminal no. 3 with the VSS disconnected, there is a short somewhere.


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If the previous tests were okay, then plug the connector back on to the VSS.

1. Jack up and properly support the car with jack stands.

2. With the ignition switch in the ON position (car not started or running), back probe the VSS orange wire terminal.

Backprobing is either using a backprobe set or using a thin needle or something and making contact with the metal terminal of the connector without piercing the wire in the back of the still connected connector. Care must be taken to ensure that the wiring does not get damaged. You can use something like a T pin, available at Walmart, etc., and backprobe. These pictures are just to give a picture of the concept of backprobing without piercing any wires.

https://www.hondaaccordforum.com/foru...%5D-t-pins-jpg

https://www.hondaaccordforum.com/foru...back-probe-jpg

Spin the passenger side wheel slowly. The voltage measurement on the VSS orange wire suppose to pulse from 0V to approx. 5V.