Pinpoint Test B: Incorrect Fuel Gauge Indication
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
Pinpoint Test B: Incorrect Fuel Gauge Indication
Refer to Wiring Diagram Set 60, Instrument Cluster for schematic and connector information. Diagrams By Number
Normal Operation
The fuel pump module is hardwired to the Instrument Cluster (IC) between the signal circuit and the signal return circuit, which is grounded internally within the IC. The fuel level sender (float and card) is a variable resistor attached to the fuel pump module that ranges from 180 ohms ± 4 ohms at empty (E) and 10 ohms± 2 ohms at full (F). The IC provides a reference voltage to the fuel pump module on the signal circuit. As the fuel level changes, a float actuates a variable resistor on the fuel level sender card and raises or lowers the fuel level signal voltage depending on the resistance of the fuel level sender. The IC monitors the changes in voltage and commands the fuel gauge with a corresponding movement of the pointer.
The IC uses 4 different operating modes to calculate the fuel level:
- Anti-slosh (default mode)
- Key OFF fueling
- Key ON fueling
- Recovery
After a fuel fill up, the time for the fuel gauge to move from empty (E) to full (F) ranges from 2 seconds to 55 minutes depending on which operating mode the fuel gauge is in.
Anti-Slosh Mode
The default fuel gauge mode is the anti-slosh mode. To prevent fuel gauge changes from fuel slosh (gauge instability due to changes in fuel sender readings caused by fuel moving around in the tank), the fuel gauge takes approximately 55 minutes to go from empty (E) to full (F).
Key OFF Fueling Mode
The key OFF fueling mode (2 seconds to read empty [E] to full [F]) requires 3 conditions be met:
- The key must be in the OFF position during the entire refueling of the vehicle.
- At least 15% of the vehicle's fuel capacity must be added to the fuel tank.
- The IC must receive a valid key ON fuel sender reading within one second of the key being placed into the RUN position. The key ON sample readings are considered valid if the fuel sender reading is between 10 ohms ± 2 ohms and 180 ohms ± 4 ohms.
If these conditions are not met, the fuel gauge stays in the anti-slosh mode, which results in a slow to read full (F) event.
Key ON Fueling Mode
The key ON fueling mode (approximately 90 seconds to read empty [E] to full [F]) requires 3 conditions be met:
- The transaxle is in PARK (P).
- The key is in the RUN position.
- At least 15% of the vehicle's fuel capacity must be added to the fuel tank.
In key ON fueling mode, a 30-second timer activates after the transaxle is placed in the PARK (P) position or when the parking brake is applied. When the 30-second time has elapsed and at least 15% of the vehicle's fuel capacity has been added, the fuel gauge response time is 90 seconds to read from empty (E) to full (F). When the transaxle is shifted out of PARK (P) or the parking brake is released, the fuel gauge strategy reverts to the anti-slosh mode. The key ON fueling mode prevents slow to read full events from happening if the customer refuels the vehicle with the key in the RUN position.
Recovery Mode
Recovery mode is incorporated into the IC strategy to recover from a missing fuel level input during a refueling event. Missing fuel level inputs result from intermittent opens in the fuel sender or its circuits. Recovery mode (empty [E] to full [F] approximately 20 minutes) is initiated when the following 2 conditions are met:
- The IC is in the anti-slosh (default) mode.
- The actual fuel level in the tank is greater than what is being displayed by the fuel gauge.
IC DTCs
PCM DTCs
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Fuel pump module
- Fuel level sender (float and card)
- Fuel tank
- IC
PINPOINT TEST B: INCORRECT FUEL GAUGE INDICATION
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
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B1 RETRIEVE THE RECORDED DTCs FROM THE IC SELF-TEST
- Check the recorded IC DTCs from the self-test.
- Are any IC DTCs recorded?
Yes
For DTC B1202, GO to B3.
For DTC B1204, GO to B7.
All other DTCs, REFER to DTC Charts. Instrumentation, Message Center and Warning Chimes
No
GO to B2.
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B2 CARRY OUT THE IC FUEL GAUGE ACTIVE COMMAND USING THE SCAN TOOL
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC DataLogger.
- Select the fuel gauge (FUEL) active command. Monitor the fuel gauge while scrolling the fuel level at 0%, 50%, and 100%.
- Does the fuel gauge display below E at 0%, half at 50%, and full at 100%?
Yes
GO to B10.
No
GO to B13.
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B3 CHECK THE FUEL PUMP MODULE FOR AN OPEN
- Ignition OFF.
- Disconnect: Fuel Pump Module C433.
- Connect a fused jumper wire between the fuel pump module C433-1, circuit RMC32 (GN/BU), harness side and the fuel pump module C433-2, circuit VMC11 (YE/VT), harness side.
- Ignition ON.
- Wait one minute.
- Enter the following diagnostic mode on the scan tool: IC Self-Test.
- NOTE: DTC B1202 may also be present when carrying out this step and should be ignored during this test step.
- Repeat the IC self-test.
- Retrieve the IC continuous DTCs.
- Is DTC B1204 retrieved?
Yes
REMOVE the jumper wire. GO to B12.
No
REMOVE the jumper wire. GO to B4.
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B4 CHECK THE FUEL LEVEL SIGNAL AND RETURN CIRCUITS FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: IC C220.
- Ignition ON.
- Measure the voltage between the IC C220-25, circuit VMC11 (YE/VT), harness side and ground; and between the IC C220-12, circuit RMC32 (GN/BU), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit in question for a short to voltage. CLEAR the DTCs. REPEAT the self-test.
No
GO to B5.
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B5 CHECK THE FUEL LEVEL SIGNAL CIRCUIT FOR AN OPEN
- Ignition OFF.
- Measure the resistance between the IC C220-25, circuit VMC11 (YE/VT), harness side and the fuel pump module C433-2, circuit VMC11 (YE/VT), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to B6.
No
REPAIR circuit VMC11 (YE/VT) for an open. CLEAR the DTCs. REPEAT the self-test.
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B6 CHECK THE FUEL LEVEL RETURN CIRCUIT FOR AN OPEN
- Measure the resistance between the IC C220-12, circuit RMC32 (GN/BU), harness side and the fuel pump module C433-1, circuit RMC32 (GN/BU), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to B13.
No
REPAIR circuit RMC32 (GN/BU) for an open. CLEAR the DTCs. REPEAT the self-test.
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B7 CHECK THE FUEL PUMP MODULE FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: Fuel Pump Module C433.
- Ignition ON.
- Wait one minute.
- Enter the following diagnostic mode on the scan tool: IC Self-Test.
- NOTE: DTC B1204 may also be present when carrying out this step and should be ignored during this test step.
- Repeat the IC self-test.
- Retrieve the IC continuous DTCs.
- Is DTC B1202 retrieved?
Yes
GO to B12.
No
GO to B8.
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B8 CHECK THE FUEL LEVEL SIGNAL AND RETURN CIRCUITS FOR A SHORT TOGETHER
- Ignition OFF.
- Disconnect: IC C220.
- Measure the resistance between the IC C220-25, circuit VMC11 (YE/VT), harness side and the IC C220-12, circuit RMC32 (GN/BU), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to B9.
No
REPAIR the circuits. CLEAR the DTCs. REPEAT the self-test.
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B9 CHECK THE FUEL LEVEL SIGNAL CIRCUIT FOR A SHORT TO GROUND
- Measure the resistance between the IC C220-25, circuit VMC11 (YE/VT), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to B13.
No
REPAIR circuit VMC11 (YE/VT) for a short to ground. CLEAR the DTCs. REPEAT the self-test.
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B10 CHECK THE IC FUEL LEVEL INPUT
NOTE: Since the IC may be in anti-slosh fuel indication mode, the PID values may not match the fuel gauge readings. The actual gauge indication should be disregarded during this test step.
- Ignition OFF.
- Disconnect: Fuel Pump Module C433.
- Connect one lead of the tester to the fuel pump module C433-1, circuit VMC11 (YE/VT), harness side and the other lead to the fuel pump module C433-2, circuit RMC32 (GN/BU), harness side.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC DataLogger.
- NOTE: It is extremely important to confirm the gauge tester settings with an ohmmeter to make sure that the gauge tester is in the correct position. Failure to follow this check may result in inaccurate test results.
- Select the IC fuel level PID (FUELLVL). Monitor the fuel level PID with the gauge tester set at 180 ohms, 90 ohms, 55 ohms, 30 ohms then 10 ohms.
- Does the PID begin at approximately 0%, move to 25%, 50%, 75% then 100%?
Yes
GO to B11.
No
GO to B13.
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B11 CHECK THE FUEL TANK
- Check the fuel tank for any damage or deformation.
- Is the fuel tank OK?
Yes
GO to B12.
No
VERIFY the fuel level sensor and fuel pump module are OK. INSTALL a new fuel tank. REFER to Fuel Tank and Lines Fuel Tank. TEST the system for normal operation.
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B12 CHECK THE FUEL LEVEL SENDER
- NOTE: The fuel level sender resistance will measure between 180 ohms ± 4 ohms at the lower stop position and 10 ohms ± 2 ohms at the upper stop position.
- Remove the fuel pump module. Refer to Fuel Tank and Lines Fuel Pump Module.
- NOTE: Disconnect the fuel level sender input wire from the fuel level sender for this measurement.
- Measure the resistance between the fuel level sender input wire and the fuel level sender ground while slowly moving the float arm between the lower stop and the upper stop position.
- Does the resistance slowly decrease from approximately 180 ohms to 10 ohms?
Yes
INSTALL a new fuel pump module. REFER to Fuel Tank and Lines Fuel Pump Module. CLEAR the DTCs. REPEAT the self-test.
No
INSTALL a new fuel level sender. CLEAR the DTCs. REPEAT the self-test.
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B13 CHECK FOR CORRECT IC OPERATION
- Disconnect all the IC connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the IC connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.
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