DTC P0187 or P0188 (LPL or LPV)
Diagnostic Instructions
DTC Descriptors
DTC P0187 00: Fuel Temperature Sensor 1
Circuit Low Voltage |
DTC P0188 00: Fuel Temperature Sensor 1
Circuit High Voltage |
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Signal
|
P0187
|
P0188
|
P0188
|
-
|
Low Reference
|
-
|
P0188
|
-
|
-
|
|
|
Typical Scan Tool Data
Fuel Temperature Sensor 1
Circuit
|
Short to Ground
|
Open
|
Short to Voltage
|
Operating Conditions: Ignition ON
Parameter Normal Range: 0.12-4.9 V
|
Signal
|
0.0 V
|
5.0 V
|
5.0 V
|
Low Reference
|
5.0 V
|
5.0 V
|
-
|
|
|
Circuit/System Description
The fuel temperature sensor is a variable resistor that measures
the temperature of the fuel. The engine control module (ECM)
supplies 5 V to the signal circuit and supplies a ground to the low
reference circuit. The following table illustrates the difference
between temperature, resistance, and voltage:
Fuel Temperature Sensor
|
Resistance
|
Signal Voltage
|
Cold
|
High
|
High
|
Warm
|
Low
|
Low
|
|
|
Conditions for Running the DTC
• |
The ignition is ON or the
engine is running. |
• |
The DTCs run continuously once
the above condition is met |
Conditions for Setting the DTC
P0187
The ECM detects that the fuel temperature sensor 1 voltage is less
than 0.127 V for 0.5 s.
P0188
The ECM detects that the fuel temperature sensor voltage 1 is
greater than 4.9 V for 0.5 s.
Action Taken When the DTC Sets
DTCs P0187 and P0188 are Type B DTCs.
Conditions for Clearing the DTC
DTCs P0187 and P0188 are Type B DTCs.
Diagnostic Aids
• |
A short to a separate 5 V
source may set a DTC P0188. |
• |
A skewed sensor may result in
poor driveability concerns. |
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
1. |
Engine running, observe the
DTC information with a scan tool. DTCs P0187, or P0188 should not
set. |
2. |
Operate the vehicle within the
Conditions for Running the DTC to verify the DTC does not reset.
You may also operate the vehicle within the conditions that you
observed from the Freeze Frame/Failure Records data. |
Circuit/System Testing
1. |
Ignition OFF, disconnect the
harness connector at the B48 Fuel Temperature Sensor. |
2. |
Test for less than 5 Ω
between the low reference circuit terminal 3 and ground.
|
⇒ |
If greater than the specified range, test the low
reference circuit for an open/high resistance. If the circuit tests
normal, replace the K20 Engine Control Module. |
3. |
Ignition ON, verify the scan
tool Fuel Temperature Sensor 1 is at -30°C (-22°F).
|
⇒ |
If greater than the specified range, test the
signal circuit terminal 1 for a short to ground. If the circuit
tests normal, replace the K20 Engine Control Module. |
|
Caution: If
the fuse in the jumper wire opens, the signal circuit may have a
short to a voltage or a short to ground and the sensor might be
damaged. |
4. |
Ignition ON, connect a 3 A
fused jumper wire between the signal circuit terminal 1 and ground.
Verify the scan tool Fuel Temperature Sensor 1 parameter is greater
than 110°C (230°F). |
⇒ |
If less than the specified range, test the signal
circuit for a short to voltage or an open/high resistance. If the
circuit tests normal, replace the K20 Engine Control Module. |
5. |
If all circuits test normal,
test or replace the B48 Fuel Temperature Sensor. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
Control Module References for ECM replacement, programming, and
setup
|