2002, Dodge Grand Caravan, 98000 miles, 3.8L engine. Fuel gauge reads quite accurately from full to about 1/2 full. Then it drops rapidly, and low fuel warning light comes on. Yet tank will only take 11 - 12 gallons upon fill-up. On-line research shows it can be one of several problems, some quite expensive to fix. How do I go about diagnosing and then fixing the problem, minimizing both diagnostic and fix-it costs.
To understand how to fix something, you need to know how it works; otherwise, you’ll have to revert to just changing parts…In this case, the fuel pump/fuel level sender.
Fuel level senders operate on the idea of electrical resistance, of a moving arm and a resistive contact strip, and of a voltage which varies dependent on the movement of that arm on that resistive strip.
One could take voltage readings, at various tank levels, to see if the voltage is varying progressively. If is isn’t, then, the fuel level sender is most likely faulty, and will need to be changed. Using a wiring diagram of the fuel level sender circuity, one could measure the voltages in the wires where they go to the dash gauge.
Does The Fuel Indicator Return To Its Proper Indication If The Van Sits With The Key Off For 10 Minutes Or So Without Doing Anything Else ?
When you look at the “date of manufacture” sticker (usually on the end of the driver’s door, is your van an early 2002, with a date earlier than 10/2001 ? (The 2002s should have begun about 7/2001).
I found a Chrysler TSB (Technical Service Bulletin) for 2001- early 2002 Caravans that describes the situation you talk about and says the vehicle has to operate for 10 minutes or at least 6 miles and then the indicator drops, but sitting 5 to 8 minutes will reset it.
The problem is that it doesn’t specifically mention “Grand” minivans, so I don’t know about this.
The fix is to inspect and reposition a kinked LDP (Leak Detection Pump) air filter hose (underneath and to the left of the power brake booster. You detach it and reposition it in a manner that eliminates the restriction. You may have to move aside any wiring or hoses that prevents a good look at the LPD air filter hose.
Let me know if any of your information voids this information and I’ll keep looking.
Do you fit all these criteria?
I Think It’s A Drive-By.