Fuel gauge quit. took to a local repair shop. sent for a sending unit(115$),total to be about 250$. dropped tank and found out 03 has two sending units. they sent only one. test did not reveal much fault with either. could not wait longer for other unit(only one car in family). they cleaned and reinstalled tank. gauge showed improvment but next day eng. chk. light came on showing fault. will have to do this all over Grrrrrr. does any one supply after mkt. parts?how hard is tank to remove after exhaust is dropped? can a shop manuel be found?
Look up "Chilton" which is a handy manual. Droping a tank, with the proper tools shouldn't be too difficult, but you will need a second hand. Make sure to purchase a few flat oil pans (even paint pans work) to collect any fuel or liquids that are hazzardous. Look up a place like a "pick-n-pull" or place where old cars go to be picked...like a junk yard. You should call the shop that worked on it at first and let them know that you found there are two sending units and they only replaced one. THey are responsible to fix the problem and not a very good mechanic if they didn't find there were two. Try to negotiate purchasing the unit, but you shouldn't have to pay for the labor since that was already paid for and wasn't done correctly. Let me know if this helps.
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what could be the problem ???? The problem is you tried to fix something you have no clue how it works .... Your best bet , take it to a qualified repair shop. You have no idea of the complexity of these cadillac systems . I know you don't have a $ 5000 dollar factory scan tool or equivalent to diagnose . The sending unit in the fuel tank is a input to the BCM . The BCM sends this info to the instrument cluster over the class 2 serial data network - communication network for the control modules on the vehicle.
The body control module (PZM) monitors the fuel level sender input in order to determine the current fuel level. The PZM filters the input and sends a message via the Class 2 serial data line. The IPC receives this message and displays the current fuel level. The fuel level is sent from the PZM to the IPC at changes of 0.5 L (0.02 gal) or on the request of the IPC, with a resolution of 0.04 L (0.01 gal).
• For the digital IPC, when the fuel level is above 18.5 gal, the IPC displays an F. For readings between 18.5-2.5 gal, whole gallon/liter numbers are displayed. When the fuel level reaches 3.0 gal the message FUEL LEVEL LOW is displayed on the driver message center. When the fuel level reaches 2.5 gal, the IPC displays an E. When the fuel level is 1.2 gal or below the IPC displays a flashing E.
• For the analog IPC, when the fuel level is above 18.5 gal, the fuel gauge pointer is on F. When the fuel level is below 2.5 gal the fuel gauge pointer moves to E. When the fuel level is below 3.0 gal the IPC displays a FUEL LEVEL LOW message.
If the updates are not received or a communication error is detected, the IPC performs the following actions:
• For the digital IPC, the fuel gauge is dashed.
• For the analog IPC, the fuel gauge pointer moves to E.
Fuel Gage Inaccurate or Inoperative
The IPC monitors the fuel level sent by the PZM through the class 2 serial data line. The IPC software controls one of the following two gauge types:
• A digital gauge consisting if a two-digit numeric seven-segment display
• An analog gauge consisting of a needle pointer.
The IPC interpolates and scales the fuel level information that the IPC receives from the PZM.
When you operate the vehicle in diagnostic mode, either in the vehicle diagnostic system or with a scan tool connected, the fuel signal supplied to the IPC is not filtered by the PZM. The unfiltered fuel signal causes the IPC to show real time readings and may be mistaken as an erratic fuel level display.
Connect a scan tool to the DLC.
Test for any set DTCs if no DTCs are set current. Refer to System Check in Body Control Module (PZM) Diagnosis.
Your best bet , take your vehicle to a qualified repair shop.
It is the fuel level gauge mounted on the sending unit. Some manufacturers just started to release this part, instead of making you buy the entire unit. They are still expensive, but not as much as a $400.00 dollar part. Shop rate on dropping the tank is 2 hours. If yours can be accessed from under the back seat then the rate is one hour.
things r common on 03 up vehicles like urs sulfar from gas can build up on ur fuel sending unit i would try some chevron with techron fuel cleaner 20oz bottle goes in the tank if that dont improve things in 2 - 3 days ur fuel sending unit is bad , and i would try use quality gas like shell, mobile, chevron if there is one where u live cause other gas doesnt meet the requirements for vehicles
It sounds like a problem with the fuel gauge sender unit in the fuel tank which has worn out and gone open circuit and needs replacing. Access to the unit is usually through a removable plate in the floor in the rear of the vehicle. Disconnect the wiring connector and any hoses and then remove the securing screws. Replacement is done by reversing procedure.
You most likely have a fuel gauge sending unit inside the tank that is failing. The part in the tank that sends the signal to the fuel gauge wears and the small sensing card wires get coated with gunk from fuel and eventually just quit sending a good signal. You could have a faulty dash servo for the gauge but the sending unit is more likely and easy for a shop to test. The sending unit on this vehicle is part of the fuel pump module and may not be serviced seperately so if it's bad you may need to buy the entire pump assembly. Good luck, hope this helps out!
The level sensor in the tank has gone bad. You can buy a fuel sending unit for about $100 (you used to have to replaced the whole tanks for hundreds of dollars, but they had so many issues they started selling the sensors on their own).
You can fix it on your own, but you're going to want the tank to be pretty much empty before hand.
hello. the fuel filter is inside the tank.it's part of the fuel sending unit.there usually good for 100,000 miles.if you wan't the fuel filter changed you have to drop the gas tank and replace the fuel sending unit.
I had the same issue with my 99 Silverado, The sending unit and fuel pump had to be replaced. (the fuel pump and sending unit are one piece units) Chevrolet dealers are aware of this issue, but its still not listed as a recall. I received a lifetime warranty w/labor when I had mine replaced. I also had an issue with the instrument cluster in dash that had to be sent out for repair unrelated to fuel gauge (speedometer)...also dropping the fuel cell is how mine was done also.
My guess would be the fuel pump purchased was bad...