Pinpoint Test B: Incorrect Fuel Gauge Indication
Instrumentation, Message Center and Warning Chimes
Pinpoint Test B: Incorrect Fuel Gauge Indication
Refer to Wiring Diagrams Set 60, Instrument Cluster for schematic and connector information. Electrical Diagrams
Normal Operation
The fuel tank is a saddle tank design with variable resistance senders, driven by floats, that provide resistances related to the fuel level in each side to the Instrument Cluster (IC). The fuel level is determined using variable resistance fuel sender units, with an approximate resistance range between 180 ohms ± 4 ohms at empty (E) and 10 ohms ± 2 ohms at full (F). The IC (Instrument Cluster) sends a reference voltage to the fuel pump module (RH side) and the fuel level sensor (LH side). As the fuel level changes, a float actuates a variable resistor on the fuel pump module and fuel level sensor, raising or lowering the fuel level signal voltage depending on the resistance of the fuel level sender (float and card). The IC (Instrument Cluster) monitors the changes in voltage from both senders and commands the fuel gauge with a corresponding movement of the pointer. If the IC (Instrument Cluster) detects the fuel level sensor circuitry is open, the fuel gauge defaults to the fuel pump module value only and the fuel gauge indicates E to one-half tank. If the IC (Instrument Cluster) detects fuel pump module circuitry is open, the fuel gauge defaults to the empty position.
The IC (Instrument Cluster) 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 called the anti-slosh mode. To prevent fuel gauge changes from fuel slosh (gauge instability due to changes in fuel sensor 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 mode when refueling the vehicle.
- At least 15% of the vehicle's fuel capacity must be added to the fuel tank.
- The IC (Instrument Cluster) must receive a valid key ON fuel sensor reading within one second of the ignition being put into the RUN mode. The key ON sample readings are considered valid if the fuel sensor 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 the following conditions be met:
- The transaxle is in PARK (P)
- The key is in the RUN mode.
- 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 put into the PARK (P) position. 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), 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 mode.
Recovery Mode
Recovery mode is incorporated into the IC (Instrument Cluster) strategy to recover from a missing fuel level input after a refueling event. Missing fuel level inputs result from intermittent opens in the fuel sensor or its circuits. Recovery mode (empty [E] to full [F] approximately 20 minutes) is initiated when the following 2 conditions are met:
- The IC (Instrument Cluster) 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.
Instrument Cluster (IC) DTCs
PCM DTCs
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Fuel tank transfer tube
- Fuel pump module
- Fuel level sensor
- Fuel level sender (float and card)
- Fuel lines
- Fuel tank
- IC (Instrument Cluster)
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.
B1 RETRIEVE THE RECORDED DTCs FROM THE IC (Instrument Cluster) SELF-TEST
- Ignition OFF.
- Check for recorded IC (Instrument Cluster) DTCs from the self-test.
Are any DTCs recorded?
Yes
For DTC B1204 or DTC B2628, GO to B3.
For DTC B1202, GO to B7.
For DTC B2627, GO to B12.
For DTC B2879, GO to B17.
No
GO to B2.
B2 CARRY OUT THE IC (Instrument Cluster) FUEL GAUGE ACTIVE COMMAND USING THE SCAN TOOL
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC (Instrument Cluster) DataLogger.
- NOTE: Make sure to set the scan tool to 0 or full empty (E) before beginning this step.
Select the IC (Instrument Cluster) fuel gauge (FUEL) active command. Command the fuel gauge from 0% to 25%, 50%, 75% and 100% while observing the fuel gauge.
Does the fuel gauge begin at (E) empty, move to approximately 1/4, 1/2, 3/4 and F (full)?
Yes
GO to B17.
No
GO to B21.
B3 CHECK THE FUEL SENDER FOR A SHORT TO GROUND
- Disconnect: Fuel Pump Module C3127 (DTC B1204) or Fuel Level Sensor C3270 (DTC B2628).
- Ignition ON.
- Wait one minute.
- Enter the following diagnostic mode on the scan tool: IC (Instrument Cluster) Self-Test.
- NOTE: DTC B1204 or DTC B2628 may also be present.
Repeat the IC (Instrument Cluster) self-test.
Is DTC B1202 or DTC B2627 retrieved?
Yes
INSTALL a new fuel pump module (DTC B1204) or fuel level sensor (DTC B2628). CLEAR the DTCs. REPEAT the self-test.
No
GO to B4.
B4 CHECK THE FUEL LEVEL SIGNAL CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: IC (Instrument Cluster) C220.
- Measure the resistance between the IC (Instrument Cluster) C220-15 (DTC B1204), circuit VMC11 (YE/VT) harness side and ground; or between the IC (Instrument Cluster) C220-14 (DTC B2628), circuit VMC23 (GN/OG) harness side and ground.
Is the resistance greater than 10,000 ohms?
Yes
For DTC B1204, GO to B5.
For DTC B2628, GO to B6.
No
REPAIR the circuit in question for a short to ground. CLEAR the DTCs. REPEAT the self-test.
B5 CHECK THE FUEL PUMP MODULE SIGNAL AND RETURN CIRCUITS FOR A SHORT TOGETHER
- Measure the resistance between the IC (Instrument Cluster) C220-15, circuit VMC11 (YE/VT), harness side and between the IC (Instrument Cluster) C220-2, circuit RMC32 (GN/BU), harness side.
Is the resistance greater than 10,000 ohms?
Yes
GO to B21.
No
REPAIR the circuit in question for a short together. CLEAR the DTCs. REPEAT the self-test.
B6 CHECK THE FUEL LEVEL SENSOR SIGNAL AND RETURN CIRCUITS FOR A SHORT TOGETHER
- Measure the resistance between the IC (Instrument Cluster) C220-14, circuit VMC23 (GN/OG), harness side and the IC (Instrument Cluster) C220-1, circuit RMC33 (WH/VT), harness side.
Is the resistance greater than 10,000 ohms?
Yes
GO to B21.
No
REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.
B7 CHECK THE FUEL PUMP MODULE CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: IC (Instrument Cluster) C220.
- Ignition ON.
- Measure the voltage between the IC (Instrument Cluster) C220-15, circuit VMC11 (YE/VT), harness side and ground; and between the IC (Instrument Cluster) C220-2, circuit RMC32 (GN/BU), harness side and ground.
Is any voltage present?
Yes
GO to B8.
No
GO to B9.
B8 CHECK THE FUEL PUMP MODULE FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Fuel Pump Module C3127.
- Ignition ON.
- Measure the voltage between the IC (Instrument Cluster) C220-15, circuit VMC11 (YE/VT), harness side and ground; and between the IC (Instrument Cluster) C220-2, 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
INSTALL a new fuel pump module. CLEAR the DTCs. REPEAT the self-test.
B9 CHECK THE FUEL PUMP MODULE CIRCUITRY FOR AN OPEN
- Ignition OFF.
- Disconnect: Fuel Pump Module C3127.
- Connect a fused jumper wire between the fuel pump module C3127-2, circuit VMC11 (YE/VT), harness side and the fuel pump module C3127-1, circuit RMC32 (GN/BU), harness side.
- Ignition ON.
- Wait one minute.
- Enter the following diagnostic mode on the scan tool: IC (Instrument Cluster) Self-Test.
- NOTE: DTC B1202 may also be present when carrying out this step and should be ignored.
Repeat the IC (Instrument Cluster) self-test.
- Retrieve the IC (Instrument Cluster) continuous DTCs.
Is DTC B1204 retrieved?
Yes
REMOVE the jumper wire. GO to B10.
No
REMOVE the jumper wire. GO to B11.
B10 CHECK THE FUEL PUMP MODULE FOR AN OPEN
NOTE: The fuel level sensor resistance varies from 180 ± 4 ohms when empty (E) to 10 ± 2 ohms when full (F).
- Measure the resistance between the fuel pump module C3127 pin 1, component side and the fuel pump module C3127 pin 2, component side.
Is the resistance within specifications?
Yes
GO to B21.
No
GO to B20.
B11 CHECK THE FUEL PUMP MODULE SIGNAL CIRCUIT FOR AN OPEN
- Measure the resistance between the IC (Instrument Cluster) C220-15, circuit VMC11 (YE/VT), harness side and the fuel pump module C3127-2, circuit VMC11 (YE/VT), harness side.
Is the resistance less than 5 ohms?
Yes
REPAIR circuit RMC32 (GN/BU) for an open. CLEAR the DTCs. REPEAT the self-test.
No
REPAIR circuit VMC11 (YE/VT). CLEAR the DTCs. REPEAT the self-test.
B12 CHECK THE FUEL LEVEL SENSOR CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: IC (Instrument Cluster) C220.
- Ignition ON.
- Measure the voltage between the IC (Instrument Cluster) C220-14, circuit VMC23 (GN/OG), harness side and ground; and between the IC (Instrument Cluster) C220-1, circuit RMC33 (WH/VT), harness side and ground.
Is any voltage present?
Yes
GO to B13.
No
GO to B14.
B13 CHECK THE FUEL LEVEL SENSOR SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Fuel Level Sensor C3270.
- Measure the voltage between the IC (Instrument Cluster) C220-14, circuit VMC23 (GN/OG), harness side and ground.
Is any voltage present?
Yes
REPAIR circuit VMC23 (GN/OG). CLEAR the DTCs. REPEAT the self-test.
No
REPAIR circuit RMC33 (WH/VT) for a short to voltage. CLEAR the DTCs. REPEAT the self-test.
B14 CHECK THE FUEL LEVEL SENSOR FOR AN OPEN
NOTE: The fuel level sensor resistance varies from 180 ± 4 ohms when empty (E) to 10 ± 2 ohms when full (F).
- Ignition OFF.
- Disconnect: Fuel Level Sensor C3270.
- Measure the resistance between the fuel level sensor C3270 pin 1, component side and the fuel level sensor C3270 pin 2, component side.
Is the resistance between 10 and 180 ohms?
Yes
GO to B15.
No
GO to B20.
B15 CHECK THE FUEL LEVEL SENSOR CIRCUITRY FOR AN OPEN
- Connect a fused jumper wire between the fuel level sensor C3270-2, circuit VMC23 (GN/OG), harness side and the fuel level sensor C3270-1, circuit RMC33 (WH/VT), harness side.
- Ignition ON.
- Wait one minute.
- Enter the following diagnostic mode on the scan tool: IC (Instrument Cluster) Self-Test.
- NOTE: DTC B2627 may also be present when carrying out this step and should be ignored.
Repeat the IC (Instrument Cluster) self-test.
- Retrieve the IC (Instrument Cluster) continuous DTCs.
Is DTC B2628 retrieved?
Yes
REMOVE the jumper wire. GO to B21.
No
REMOVE the jumper wire. GO to B16.
B16 CHECK THE FUEL LEVEL SENSOR SIGNAL CIRCUIT FOR AN OPEN
- Measure the resistance between the IC (Instrument Cluster) C220-14, circuit VMC23 (GN/OG), harness side and the fuel level sensor C3270-2, circuit VMC23 (GN/OG), harness side.
Is the resistance less than 5 ohms?
Yes
REPAIR circuit RMC33 (WH/VT) for an open. CLEAR the DTCs. REPEAT the self-test.
No
REPAIR circuit VMC23 (GN/OG). CLEAR the DTCs. REPEAT the self-test.
B17 INSPECT THE FUEL TANK
- Visually inspect the fuel tank for any damage or deformation.
Is the fuel tank OK?
Yes
GO to B18.
No
INSTALL a new fuel tank. CLEAR the DTCs. REPEAT the self test.
B18 INSPECT THE FUEL TANK TRANSFER TUBE CONNECTIONS
- Remove the fuel pump module and the fuel level sensor.
- Inspect the fuel tank transfer tube, connections, the fuel pump module and the fuel level sensor for any damage or deformation.
Are the fuel tank transfer tube, connections, the fuel pump module and the fuel level sensor OK?
Yes
GO to B19.
No
INSTALL a new fuel tank transfer tube, fuel pump module or fuel level sensor as necessary. CLEAR the DTCs. REPEAT the self test.
B19 CHECK THE FUEL PUMP MODULE AND THE FUEL LEVEL SENSOR FOR CORRECT OPERATION
NOTE: The resistance varies from 180 ± 4 ohms when empty (E) to 10 ± 2 ohms when full (F).
- For the fuel pump module, measure the resistance between the fuel pump module C3127 pin 1, component side and the fuel pump module C3127 pin 2, component side while slowly moving the float arm from the bottom to the top of travel.
- For the fuel level sensor, measure the resistance between the fuel level sensor C3270 pin 1, component side and the fuel level sensor C3270 pin 2, component side while slowly moving the float arm from the bottom to the top of travel.
Does the resistance start at approximately 180 ohms with the float at the bottom of travel and slowly decrease to approximately 10 ohms at the top of travel?
Yes
For DTC B2879, INSTALL a new fuel tank transfer tube or fuel level sensor as required. CLEAR the DTCs. REPEAT the self test.
For no DTCs, the concern may have been caused by an intermittent input to the IC (Instrument Cluster) most likely caused by corrosion on one of the fuel level sensors (float and card).
No
For the fuel pump module, GO to B20.
For the fuel level sensor, INSTALL a new fuel level sensor. CLEAR the DTCs. REPEAT the self-test.
B20 CHECK THE FUEL LEVEL SENDER (FLOAT AND CARD)
NOTE: The fuel level sender (float and card) resistance measures 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 or fuel level sensor.
- NOTE: Disconnect the fuel level sender (float and card) input wire from the fuel pump module for this measurement.
Measure the resistance between the fuel level sender (float and card) input wire and the fuel level sender (float and card) ground while slowly moving the float arm between the lower and upper stop position.
Does the resistance slowly decrease from approximately 180 ohms at the lower stop to 10 ohms at the upper stop?
Yes
INSTALL a new fuel pump module or fuel level sensor as necessary. CLEAR the DTCs. REPEAT the self-test.
No
INSTALL a new fuel level sender (float and card). CLEAR the DTCs. REPEAT the self-test.
B21 CHECK FOR CORRECT IC (Instrument Cluster) OPERATION
- Disconnect the IC (Instrument Cluster) connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the IC (Instrument Cluster) connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
Is the concern still present?
Yes
INSTALL a new IC (Instrument Cluster). REFER to 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.