The fuel tank temperature (FTT) sensor is a variable resistor that measures the temperature of the fuel in the CNG fuel tank. The PCM supplies a 5 volt reference circuit and a signal circuit to the FTT sensor. This DTC sets when the FTT signal voltage is above the normal operating range of the sensor.
• | DTCs P0112, or P0113 are not set. |
• | The intake air temperature is less than 30°C (86°F). |
• | The fuel tank temperature sensor voltage is more than 4.95 volt. |
• | The condition exists for more than 3 seconds. |
• | The powertrain control module (PCM) stores the DTC information into memory when the diagnostic runs and fails. |
• | The malfunction indicator lamp (MIL) will not illuminate. |
• | The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records. |
• | A last test failed, or current DTC, clears when the diagnostic runs and does not fail. |
• | A history DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic. |
• | Use a scan tool in order to clear the DTC. |
• | Use the Temperature vs Resistance table in order to test the FTT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor could result in a driveability condition. If the engine has sat overnight, the FTT sensor and the intake air temperature values should display within a few degrees. If the temperatures are not within 3°C (5°F), refer to Fuel Temperature Sensor Output Voltage Versus Temperature Resistance . |
• | For an intermittent condition, refer to Intermittent Conditions . |
The numbers below refer to the step numbers on the diagnostic table.
This step verifies that a condition exists.
This step tests the signal circuit of the FTT sensor for a short to voltage. The scan tool should display 0 volts when the FTT sensor is disconnected.
This step tests the 5 volt reference circuit of the FTT sensor for a short to voltage. The 5 volt reference circuits of the FTP, FTT and FRP are shared internally and externally of the PCM.
Step | Action | Values | Yes | No | ||||||
---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views | ||||||||||
1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | -- | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) | ||||||
Does the scan tool indicate that the FTT is near the specified value? | 5 V | Go to Step 4 | Go to Step 3 | |||||||
3 |
Does the DTC fail this ignition cycle? | -- | Go to Step 4 | Go to Diagnostic Aids | ||||||
Does the scan tool indicate that the FTT sensor is at the specified value? | 0 V | Go to Step 5 | Go to Step 6 | |||||||
Observe the fuel tank pressure (FTP) parameter with a scan tool. Does the scan tool indicate that the FTP sensor is the same or more than the specified value? | 4.8 V | Go to Step 7 | Go to Step 8 | |||||||
6 | Test the signal circuit of the FTT sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems in the J Platform Service Manual. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9 | ||||||
7 | Test the following circuits for a short to voltage:
Refer to Circuit Testing and Wiring Repairs in Wiring Systems in the J Platform Service Manual. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9 | ||||||
8 | Replace the FTT sensor. The FTT sensor is not serviceable separately from the HPL. Refer to High Pressure Lock-Off Solenoid Replacement . Did you complete the replacement? | -- | Go to Step 10 | -- | ||||||
9 | Replace the PCM. Refer to Powertrain Control Module Replacement in the J Platform Service Manual. Did you complete the replacement? | -- | Go to Step 10 | -- | ||||||
10 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 11 | ||||||
11 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK |