Diagnostic Routine B
Diagnostic Routine B
Diagnostic Overview
Incorrect Fuel Gauge Indication
Refer to Wiring Diagram Set 60 for schematic and connector information Electrical Diagrams.
Normal Operation and Fault Conditions
The fuel gauge uses inputs from the fuel pump assembly and the fuel level sender to provide the fuel level indication. REFER to Fuel Gauge and REFER to Fuel Level Sender .
IPC (Instrument Panel Cluster) DTC Fault Trigger Conditions
BCM (Body Control Module) DTC Fault Trigger Conditions
PCM (Powertrain Control Module) DTC Fault Trigger Conditions
Visual Inspection and Diagnostic Pre-checks
Inspect the fuel tank for signs of damage that can affect the float operation inside the tank. Inspect the fuel gauge needle in the IPC (Instrument Panel Cluster) for signs of binding or damage.
Special Tool(s)
Pinpoint Test
1. CARRY OUT THE IPC (Instrument Panel Cluster) SELF-TEST
1. Using a scan tool, perform the IPC (Instrument Panel Cluster) self-test.
2. Check for recorded DTCs (Diagnostic Trouble Codes) from the IPC (Instrument Panel Cluster) self-test.
Is DTC (Diagnostic Trouble Code) U0140:00 recorded?
2. CARRY OUT THE BCM (Body Control Module) SELF-TEST
1. Using a scan tool, perform the BCM (Body Control Module) self-test.
2. Check for recorded DTCs (Diagnostic Trouble Codes) from the BCM (Body Control Module) self-test.
Are any DTCs (Diagnostic Trouble Codes) recorded?
3. CHECK THE FUEL INPUT FOR A SHORT TO GROUND
1. Disconnect: Fuel Pump Assembly.
2. Ignition ON.
3. Wait one minute.
4. NOTE: DTC (Diagnostic Trouble Code) P0460:21 can also be present.
Using a scan tool, repeat the BCM (Body Control Module) on-demand self-test.
Is DTC (Diagnostic Trouble Code) P0460:22 retrieved?
4. CHECK THE FUEL PUMP ASSEMBLY AND FUEL LEVEL SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND
1. Ignition OFF.
2. Disconnect: BCM (Body Control Module) C2280B.
3. Measure:
Is the resistance greater than 10,000 ohms?
5. CHECK THE FUEL PUMP ASSEMBLY SIGNAL AND RETURN CIRCUITS FOR A SHORT TOGETHER
1. Measure:
Is the resistance greater than 10,000 ohms?
6. CHECK THE FUEL PUMP ASSEMBLY FOR AN OPEN
1. Ignition OFF.
2. Disconnect: Fuel Pump Assembly.
3. Connect a fused jumper wire:
4. Ignition ON.
5. Wait one minute.
6. NOTE: DTC (Diagnostic Trouble Code) P0460:21 can also be present when carrying out this step and should be ignored at this time.
Using a scan tool, repeat the BCM (Body Control Module) self-test.
7. Retrieve the BCM (Body Control Module) continuous DTCs (Diagnostic Trouble Codes).
Is DTC (Diagnostic Trouble Code) P0460:22 retrieved?
7. CHECK THE FUEL LEVEL SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
1. Ignition OFF.
2. Disconnect: BCM (Body Control Module) C2280B.
3. Ignition ON.
4. Measure:
Is any voltage present?
8. CHECK THE FUEL LEVEL SIGNAL CIRCUIT FOR AN OPEN
1. Ignition OFF.
2. Measure:
Is the resistance less than 3 ohms?
9. CHECK THE FUEL LEVEL RETURN CIRCUIT FOR AN OPEN
1. Measure:
Is the resistance less than 3 ohms?
10. CHECK THE FUEL GAUGE OPERATION USING THE DEALER TEST MODE
1. Ignition ON.
2. Monitor the fuel gauge.
3. Ignition OFF.
4. Enter the Dealer Test Mode. REFER to Dealer Test Mode .
5. Scroll to gauge sweep.
6. Monitor the fuel gauge when the gauge sweep initiates.
Does the fuel gauge begin at empty (E), sweep to full (F) then return to empty (E)?
11. CHECK THE FUEL PUMP ASSEMBLY SIGNAL AND RETURN CIRCUITS FOR HIGH RESISTANCE
1. Ignition OFF.
2. Disconnect: BCM (Body Control Module) C2280B.
3. Disconnect: Fuel Pump Assembly.
4. Connect a fused jumper wire:
5. Measure:
Is the resistance less than 3 ohms?
12. INSPECT THE FUEL TANK
1. Visually inspect the fuel tank for any damage or deformation.
Is the fuel tank OK?
13. INSPECT THE FUEL TANK AND FUEL LEVEL SENDER
1. Remove the fuel pump assembly. REFER to Fuel Pump Assembly .
2. Inspect the fuel pump assembly and the fuel level sender for any damage or deformation.
Are the fuel pump assembly and the fuel level sender OK?
14. CHECK THE FUEL PUMP ASSEMBLY AND THE FUEL LEVEL SENSOR FOR CORRECT OPERATION
1. NOTE: The fuel resistance measures between 51 ohms± 2 ohms at the upper stop position and 464 ohms± 4 ohms at the lower stop position.
Measure:
Is the resistance between 464 ohms 51 ohms?
15. CHECK THE FUEL PUMP ASSEMBLY
1. Remove the fuel pump assembly. REFER to Fuel Pump Assembly .
2. NOTE: The fuel resistance measures between 51 ohms± 2 ohms at the upper stop position and 464 ohms± 4 ohms at the lower stop position.
While moving the float from the bottom to the top, measure:
Does the resistance start at approximately 464 ohms with the float at the bottom of travel and slowly decrease to approximately 51 ohms at the top of travel?
16. CHECK THE FUEL LEVEL SENDER
1. Disconnect the fuel level sender input wire from the fuel pump assembly.
2. NOTE: The fuel level sender resistance measures between 51 ohms± 2 ohms at the upper stop position and 464 ohms± 4 ohms at the lower stop position.
Measure the resistance while slowly moving the float arm between the lower and upper stop position.
Does the resistance slowly decrease from approximately 464 ohms to 51 ohms?
17. CHECK FOR CORRECT BCM (Body Control Module) OPERATION
1. Ignition ON.
2. Disconnect and inspect all BCM (Body Control Module) connectors.
3. Repair:
- corrosion (install new connector or terminals- clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary
4. Reconnect the BCM (Body Control Module) connectors. Make sure they seat and latch correctly.
5. Operate the system and determine if the concern is still present.
Is the concern still present?
