Volvo 240 1990 Speedometer Works Randomly
This topic is in the MVS Volvo Repair Database »
1998 V70R Turbo vacuum line - How to get it off?
Volvo 240 1990 Speedometer Works Randomly
Hello everyone! I have a 1990 Volvo 240 Sedan, and the speedometer is not working. It has not fully died, it works once in a while. It will just pop on while driving seldomly. The odometer will work only when the speedometer is functioning. Any ideas on what the problem might be? Thanks!
-
billofdurham
- MVS Moderator
- Posts: 6507
- Joined: 2 February 2006
- Year and Model: 855, 1995
- Location: Durham, England
- Been thanked: 5 times
Welcome to Matthew's Volvo Site.
First check the connection at the speedo sensor. It's in the differential cover, about 3" above the filler plug. Ensure it's secure and check the contacts on both the sensor and the connector for signs of corrosion or oxidation. If there is, spray with electronic deoxidizer and clean it. You can take off the old plug and rewire it with new connectors that you can seal up with silicone sealer. Examine the harness for any signs of a break or tear, or for signs the wire might have been cut. It has been known for the safety wire to cut through the wires from the connector to the speedo so pay close attention to that. If it's not wiring, then it's either the sensor or the speedometer head.
A very effective and easy way to diagnose the sensor is to disconnect the connector on the differential case and connect two long pieces of wires to the plug coming from the vehicle wiring. Bring the extension wires inside the car, start the engine, and start shorting the wires at a pace of 4-5 shorts per second. If the gauge is OK you should start to read a speed over 15MPH. The faster you short, the higher the speed.
Bill.
First check the connection at the speedo sensor. It's in the differential cover, about 3" above the filler plug. Ensure it's secure and check the contacts on both the sensor and the connector for signs of corrosion or oxidation. If there is, spray with electronic deoxidizer and clean it. You can take off the old plug and rewire it with new connectors that you can seal up with silicone sealer. Examine the harness for any signs of a break or tear, or for signs the wire might have been cut. It has been known for the safety wire to cut through the wires from the connector to the speedo so pay close attention to that. If it's not wiring, then it's either the sensor or the speedometer head.
A very effective and easy way to diagnose the sensor is to disconnect the connector on the differential case and connect two long pieces of wires to the plug coming from the vehicle wiring. Bring the extension wires inside the car, start the engine, and start shorting the wires at a pace of 4-5 shorts per second. If the gauge is OK you should start to read a speed over 15MPH. The faster you short, the higher the speed.
Bill.
Work was good - retirement is better.
1996 850GLT 2.5 20v Estate Manual.
1995 Peugeot Boxer 2.5Tdi Autosleeper.
Previously:
1984 244DL, Manual, Beige.
1987 744GLE, Manual, Green.
1991 960 3.0 24v, Auto, Silver.
1994 940T Wentworth, Auto, Blue.
1996 850GLT 2.5 20v Estate Manual.
1995 Peugeot Boxer 2.5Tdi Autosleeper.
Previously:
1984 244DL, Manual, Beige.
1987 744GLE, Manual, Green.
1991 960 3.0 24v, Auto, Silver.
1994 940T Wentworth, Auto, Blue.
-
rob2volvos
- Posts: 20
- Joined: 26 January 2010
- Year and Model: 1992 740 / 1994 940
- Location: Charlottesville, VA
I had exactly the same problem as this recently on my 1992 740.
I did most of the things Bill outlines in his post and traced the fault to the speedometer itself. I understand the speedometer capacitors tend to leak and that could be your problem. (Not necessarily the answer to your problem -- but the symptoms you describe are just like mine). Anyway -- here's my story:
http://www.brickboard.com/RWD/volvo/145 ... _luck.html
One of these days I'm expecting to have to replace all the offending capacitors in the speedo -- but maybe I'll expire before they do --
Hope this helps,
Rob
I did most of the things Bill outlines in his post and traced the fault to the speedometer itself. I understand the speedometer capacitors tend to leak and that could be your problem. (Not necessarily the answer to your problem -- but the symptoms you describe are just like mine). Anyway -- here's my story:
http://www.brickboard.com/RWD/volvo/145 ... _luck.html
One of these days I'm expecting to have to replace all the offending capacitors in the speedo -- but maybe I'll expire before they do --
Hope this helps,
Rob
-
- Similar Topics
- Replies
- Views
- Last post