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I have a question regarding my 1990 Vanden Plas. My check engine light turns on sometimes but I bypass it by turning the car off and then on again and the light disappears, is this ok? Can anyone tell me if there is something wrong with darling.
It's a 1990 Vanden Plas with almost 90k miles on the dash. My VIN is SAJJKYLD4LS593006. Is this a common thing that happens to the car electrically? It also does it with my Light Bulb on the dash, here and there it will go on and off but everything runs well and smooth. I did check that my oil is low and has a leak within the engine. I know my Power Steering Rod is leaking and the mechanic said it'll cost me a good amount to repair. I got the car in June with 87k miles and have driven it daily since it's my first and only car.
It may be that the check engine light is on, but because of an intermittent connection, it appears to go on and off? You can check if there any trouble codes stored if you turn on the ign (but don't start the car) and then press the VCM button.
If you have a check engine fault, you'll see a code displayed on the dash, e.g. Fuel Fail and a number or FF and a number.
The display instrument binnacle solder connections do fail on these cars and can be repaired by reflowing the solder joints.
Leaks, although annoying and messy, won't cause the check engine light to illuminate. Only a sensor can report a fault that causes the lamp to light. On a late car, the check engine light won't reset each time you switch off the car, at least it won't on my 94 ..maybe someone with a 1990 car can confirm if the lamp resets when the engine is restarted?
Larry
Last edited by Lawrence; Dec 16, 2019 at 02:20 AM.
Congratulations on your low-mileage XJ40! We'd all love to see some photos when you get a chance to upload some.
If you'll follow Larry's instructions for retrieving any diagnostic trouble codes, you can reference this chart to find the area of the malfunction:
Post your codes here and we'll try to help you resolve them. Note that while most of the codes are related to emissions, the problems that can trigger some of the codes can lead to running conditions that can damage expensive components such as catalytic converters, valves, etc., so you don't want to ignore what your Jag is trying to tell you.
Check Engine Light On and Off
