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 tank is a saddle tank design with 2 variable resistance senders, driven by floats, that provide resistances related to fuel level in each side of the fuel tank to the Instrument Panel Cluster (IPC). 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 IPC is hardwired to both the fuel pump module and fuel level sensor through signal and return circuits. The IPC sends a reference voltage to the fuel pump module and the fuel level sensor through the fuel level signal circuit. 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 IPC monitors the changes in voltage from both sensors, calculates the fuel level, then combines the calculated fuel level from both senders and commands the fuel gauge. If the IPC detects a fault in the fuel pump module or the fuel level sensor circuitry, the fuel gauge defaults to the empty position.

The IPC 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 the following conditions be met:

- The ignition 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 IPC must receive a valid ignition 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 60 seconds to read empty [E] to full [F]) requires the following conditions be met:

- The transaxle is in PARK (P) or NEUTRAL (N).
- The ignition 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) or NEUTRAL (N) 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 60 seconds to read from empty (E) to full (F). When the transaxle is shifted out of PARK (P) or NEUTRAL (N), 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 ignition in the RUN mode.

Recovery Mode

Recovery mode is incorporated into the IPC 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 conditions are met:

- The IPC 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 Panel Cluster (IPC) 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
- IPC

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.

NOTE: Following any fuel gauge repairs, remove fuse 26 (10A) for one minute then reinstall to reset the fuel gauge timers.

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B1 RETRIEVE THE RECORDED DTCs FROM THE IPC SELF-TEST

- Ignition OFF.
- Check for recorded DTCs from the IPC self-test.
- Are any DTCs recorded?

Yes
For DTC P0460:11 or DTC P1346:11, GO to B3.

For DTC P0460:13, GO to B7.

For DTC P1346:13, GO to B11.

For DTC P1243:06, GO to B15.

No
GO to B2.

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B2 CARRY OUT THE IPC FUEL GAUGE ACTIVE COMMAND USING THE SCAN TOOL

- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IPC DataLogger.
- Select the IPC fuel gauge (FuelLevel) 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 B15.

No
GO to B21.

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B3 CHECK THE FUEL SENSOR FOR A SHORT TO GROUND

- Disconnect: Fuel Pump Module C3127 (DTC P0460:11) or Fuel Level Sensor C3270 (DTC P1346:11).
- Ignition ON.
- Wait one minute.
- Enter the following diagnostic mode on the scan tool: IPC Self-Test.
- NOTE: DTC P0460:11 or P1346:11 may also be present.
- Repeat the IPC on-demand self-test.
- Is DTC P0460:13 or DTC P1346:13 retrieved?

Yes
INSTALL a new fuel pump module (DTC P0460:11) or fuel level sensor (DTC P1346:11). REFER to Fuel Delivery and Air Induction. CLEAR the DTCs. REPEAT the self-test.

No
GO to B4.

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B4 CHECK THE FUEL LEVEL SIGNAL CIRCUITS FOR A SHORT TO GROUND

- Ignition OFF.
- Disconnect: IPC C220.
- Measure the resistance between the IPC C220-15 (DTC P0460:11), circuit VMC11 (YE/VT), harness side and ground; or between the IPC C220-14 (DTC P1346:11), circuit VMC23 (GN/OG), harness side and ground.

- Is the resistance greater than 10,000 ohms?

Yes
For DTC P0460:11, GO to B5.

For DTC P1346:11, GO to B6.

No
REPAIR the circuit in question for a short to ground. CLEAR the DTCs. REPEAT the self-test.

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B5 CHECK THE FUEL PUMP MODULE SIGNAL AND RETURN CIRCUITS FOR A SHORT TOGETHER

- Measure the resistance between the IPC C220-15, circuit VMC11 (YE/VT), harness side and between the IPC C220-2, circuit RMC32 (GN/WH), harness side.

- Is the resistance greater than 10,000 ohms?

Yes
GO to B21.

No
REPAIR the circuits. CLEAR the DTCs. REPEAT the self-test.

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B6 CHECK THE FUEL LEVEL SENSOR SIGNAL AND RETURN CIRCUITS FOR A SHORT TOGETHER

- Measure the resistance between the IPC C220-14, circuit VMC23 (GN/OG), harness side and the IPC C220-1, circuit RMC33 (WH/VT), harness side.

- Is the resistance greater than 10,000 ohms?

Yes
GO to B21.

No
REPAIR the circuits. CLEAR the DTCs. REPEAT the self-test.

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B7 CHECK THE FUEL PUMP MODULE FOR AN OPEN

- Ignition OFF.
- Disconnect: Fuel Pump Module C3127.
- Connect a fused jumper wire between the fuel pump module C3127-1, circuit RMC32 (GN/WH), harness side and the fuel pump module C3127-2, circuit VMC11 (YE/VT), harness side.

- Ignition ON.
- Wait one minute.
- Enter the following diagnostic mode on the scan tool: IPC Self-Test.
- NOTE: DTC P0460:13 may also be present when carrying out this step and should be ignored at this time.
- Repeat the IPC self-test.
- Retrieve the IPC continuous DTCs.
- Is DTC P0460:11 retrieved?

Yes
REMOVE the jumper wire. GO to B20.

No
REMOVE the jumper wire. GO to B8.

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B8 CHECK THE FUEL LEVEL SIGNAL AND RETURN CIRCUITS FOR A SHORT TO VOLTAGE

- Ignition OFF.
- Disconnect: IPC C220.
- Ignition ON.
- Measure the voltage between the IPC C220-15, circuit VMC11 (YE/VT), harness side and ground; and between the IPC C220-2, circuit RMC32 (GN/WH), 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 B9.

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B9 CHECK THE FUEL LEVEL SIGNAL CIRCUIT FOR AN OPEN

- Ignition OFF.
- Measure the resistance between the IPC C220-15, circuit VMC11 (YE/VT), harness side and the fuel pump module assembly C3127-2, circuit VMC11 (YE/VT), harness side.

- Is the resistance less than 5 ohms?

Yes
GO to B10.

No
REPAIR the circuit VMC11 (YE/VT) for an open. CLEAR the DTCs. REPEAT the self-test.

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B10 CHECK THE FUEL LEVEL RETURN CIRCUIT FOR AN OPEN

- Measure the resistance between the IPC C220-2, circuit RMC32 (GN/WH), harness side and the fuel pump module assembly C3127-1, circuit RMC32 (GN/WH), harness side.

- Is the resistance less than 5 ohms?

Yes
GO to B21.

No
REPAIR circuit RMC32 (GN/WH). CLEAR the DTCs. REPEAT the self-test.

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B11 CHECK THE FUEL LEVEL SENSOR CIRCUITRY FOR AN OPEN

- Disconnect: Fuel Level Sensor C3270.
- 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: IPC Self-Test.
- NOTE: DTC P1346:13 may also be present when carrying out this step and should be ignored at this time.
- Repeat the IPC self-test.
- Retrieve the IPC continuous DTCs.
- Is DTC P1346:11 retrieved?

Yes
REMOVE the jumper wire. INSTALL a new fuel level sensor. REFER to Fuel Delivery and Air Induction. CLEAR the DTCs. REPEAT the self-test.

No
REMOVE the jumper wire. GO to B12.

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B12 CHECK THE FUEL LEVEL SENSOR CIRCUITRY FOR A SHORT TO VOLTAGE

- Disconnect: IPC C220.
- Ignition ON.
- Measure the voltage between the IPC C220-14, circuit VMC23 (GN/OG), harness side and ground; and between the IPC C220-1, circuit RMC33 (WH/VT), 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 B13.

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B13 CHECK THE FUEL LEVEL SENSOR SIGNAL CIRCUIT FOR AN OPEN

- Measure the resistance between the IPC 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
GO to B14.

No
REPAIR circuit VMC23 (GN/OG) for an open. CLEAR the DTCs. REPEAT the self-test.

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B14 CHECK THE FUEL LEVEL SENSOR RETURN CIRCUIT FOR AN OPEN

- Measure the resistance between the IPC C220-1, circuit RMC33 (WH/VT), harness side and the fuel level sensor C3270-1, circuit RMC33 (WH/VT), harness side.

- Is the resistance less than 5 ohms?

Yes
GO to B21.

No
REPAIR circuit RMC33 (WH/VT) for an open. CLEAR the DTCs. REPEAT the self-test.

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B15 CHECK THE FUEL PUMP MODULE INPUT TO THE IPC

NOTE: Since the IPC may be in anti-slosh fuel indication mode, the self-test and tester 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 Assembly C3127.
- Connect one lead of the instrument gauge system tester to the fuel pump module assembly C3127-2, circuit VMC11 (YE/VT), harness side and the other lead to the fuel pump module assembly C3127-1, circuit RMC32 (GN/WH), harness side.

- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IPC PIDs.
- 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.
- Monitor the IPC fuel level (FUELLVL2) PID, with the gauge tester set at 180 ohms, 90 ohms, 55 ohms, 30 ohms and 10 ohms.
- Does the PID begin at approximately 3 move to 70, 127, 185 then 251?

Yes
DISCONNECT the instrument gauge system tester. GO to B17.

No
DISCONNECT the instrument gauge system tester. GO to B21.

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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. REFER to Fuel Delivery and Air Induction. CLEAR the DTCs. REPEAT the self test.

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B18 INSPECT THE FUEL TANK TRANSFER TUBE CONNECTIONS

- Remove the fuel pump module and the fuel level sensor. Refer to Fuel Delivery and Air Induction.
- 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. REFER to Fuel Delivery and Air Induction. CLEAR the DTCs. REPEAT the self test.

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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 increase to approximately 10 ohms at the top of travel?

Yes
For DTC P1243:06, INSTALL a new fuel tank transfer tube or fuel level sensor as required. REFER to Fuel Delivery and Air Induction. CLEAR the DTCs. REPEAT the self test.

For no DTCs, the concern may have been caused by an intermittent input to the IPC most likely caused by corrosion on one of the fuel level senders (float and card).

No
For the fuel pump module, GO to B20.

For the fuel level sensor, INSTALL a new fuel level sensor. REFER to Fuel Delivery and Air Induction. CLEAR the DTCs. REPEAT the self-test.

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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. Refer to Fuel Delivery and Air Induction.
- 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. REFER to Fuel Delivery and Air Induction. CLEAR the DTCs. REPEAT the self-test.

No
INSTALL a new fuel level sender (float and card). REFER to Fuel Delivery and Air Induction. CLEAR the DTCs. REPEAT the self-test.

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B21 CHECK FOR CORRECT IPC OPERATION

- Disconnect the IPC connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the IPC 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 IPC. REFER to Instrument Panel Cluster (IPC) Instrument Panel Cluster (IPC). 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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