Pinpoint Tests AK: The Water In Fuel Message Center Indicator Is Never/Always On
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
Pinpoint Test AK: The Water In Fuel Message Center Indicator Is Never/Always On
Refer to Wiring Diagram Set 26, Electronic Engine Controls - 6.7L Diesel for schematic and connector information. Diagrams By Number
Normal Operation
The water in fuel data is transmitted to the Instrument Panel Cluster (IPC) from the PCM over the High Speed Controller Area Network (HS-CAN) communication bus. The water in fuel sensor receives a reference voltage from the PCM through separate input and return circuits. When water is detected in the fuel, the water in fuel sensor pulls the reference voltage low to the PCM. The PCM then sends a command to the IPC to illuminate the message center indicator.
If the water in fuel status is missing for less than 5 seconds, the water in fuel indicator remains in the last indication state (on or off), based upon the last known good water in fuel status message received. If the water in fuel data is missing for more than 5 seconds or more, the IPC sets DTC U0100:00 in continuous memory and defaults the water in fuel indicator inactive (off).
NOTE: If DTC U0100:00 sets in the IPC, other observable symptoms may be an inoperative speedometer, tachometer or odometer.
This pinpoint test is intended to diagnose the following:
- Message center concern
- Water in fuel contamination
- Wiring, terminals or connectors
- Water in fuel sensor
- PCM
PINPOINT TEST AK: THE WATER IN FUEL MESSAGE CENTER INDICATOR IS NEVER/ALWAYS ON
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AK1 VERIFY THE OPERATION OF THE DOOR AJAR MESSAGE CENTER WARNING INDICATOR
- Close all doors then open the LH front door.
- Ignition ON.
- NOTE: If multiple warnings are present, the message center cycles through each of the warning indicators. Allow the displays to cycle through each display while determining whether the door ajar message center warning indicator is active.
- Observe the message center.
- Is the door ajar message center telltale warning indicator active?
Yes
If the water in fuel message center warning indicator is never on, GO to AK2. If the water in fuel message center warning indicator is always on, GO to AK3.
No
GO to Pinpoint Test AN. Pinpoint Tests AN: The Door Ajar Message Center Warning Indicator Is Never/Always On
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AK2 RETRIEVE THE RECORDED DTCs FROM THE IPC SELF-TEST
- Check for recorded IPC DTCs from the self-test.
- Are any DTCs recorded?
Yes
For DTC U0100:00, GO to Pinpoint Test BA. For all other DTCs, REFER to DTC Charts. Pinpoint Tests BA: DTC U0100:00
No
GO to AK5.
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AK3 CHECK THE WATER IN FUEL SENSOR OPERATION (ALWAYS ON)
- Ignition OFF.
- Disconnect: Water In Fuel Sensor C1080.
- Ignition ON.
- Does the water in fuel message center indicator turn off?
Yes
CHECK the fuel system for water contamination. If water contamination exists, DRAIN the water from the fuel system. REFER to Fuel System - General Information - Gasoline and Diesel Procedures. TEST the system for normal operation. If no water contamination is found, INSTALL a new water in fuel sensor. REFER to Fuel Tank and Lines - Gasoline and Diesel Service and Repair. TEST the system for normal operation.
No
GO to AK4.
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AK4 CHECK THE WATER IN FUEL INPUT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: PCM C1232b.
- Measure the resistance between the PCM C1232b-12, circuit VE823 (BU/BN), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to AK8.
No
REPAIR the circuit. TEST the system for normal operation.
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AK5 CHECK THE WATER IN FUEL SENSOR OPERATION (NEVER ON)
- Ignition OFF.
- Disconnect: Water In Fuel Sensor C1080.
- Connect a fused jumper wire between the water in fuel sensor C1080-2, circuit VE823 (BU/BN), harness side and ground.
- Ignition ON.
- Wait approximately 4 minutes.
- Does the water in fuel message center indicator illuminate?
Yes
GO to AK6.
No
GO to AK7.
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AK6 CHECK THE WATER IN FUEL RETURN FOR AN OPEN
- Ignition OFF.
- Disconnect: PCM C1232b.
- Measure the resistance between the water in fuel sensor C1080-1, circuit RE407 (YE/VT), harness side and the PCM C1232b-13, circuit RE407 (YE/VT), harness side.
- Is the resistance less than 5 ohms?
Yes
VERIFY the fuel system has sufficient water contamination to turn on the water in fuel message center indicator.
If insufficient water contamination is found, the system is operating normally at this time. If sufficient water contamination exists, INSTALL a new water in fuel sensor. REFER to Fuel Tank and Lines - Gasoline and Diesel Service and Repair. TEST the system for normal operation.
No
REPAIR the circuit. TEST the system for normal operation.
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AK7 CHECK THE WATER IN FUEL INPUT FOR AN OPEN
- Ignition OFF.
- Disconnect: PCM C1232b.
- Measure the resistance between the water in fuel sensor C1080-2, circuit VE823 (BU/BN), harness side and the PCM C1232b-12, circuit VE823 (BU/BN), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to AK8.
No
REPAIR the circuit. TEST the system for normal operation.
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AK8 CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the PCM 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 PCM. REFER to Electronic Engine Controls - Diesel Engine Powertrain Control Module (PCM). 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.
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