DTC P0131, P0132, P0137, or P0138 - LDE or LLU
Diagnostic Instructions
DTC Descriptors
DTC P0131 00: HO2S Circuit Low Voltage
Sensor 1
DTC P0132 00: HO2S Circuit High Voltage
Sensor 1
DTC P0137 00: HO2S Circuit Low Voltage
Sensor 2
DTC P0138 00: HO2S Circuit High Voltage
Sensor 2
Diagnostic Fault Information
HO2S 1
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
HO2S 1 Signal
|
P0131 00, P0171 00
|
P0132 00, P0134 00, P0137 00, P2A00 00
|
P0132 00, P0134 00
|
P0133 00, P1133 00, P2A00 00
|
Low Reference
|
-
|
P0134 00, P0137 00
|
-
|
P0133 00, P1133 00, P2A00 00
|
HO2S 2
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
HO2S 2 Signal
|
P0137 00
|
P0138 00, P0140 00
|
P0132 00, P0134 00
|
-
|
Low Reference
|
-
|
P0138 00, P0140 00
|
-
|
-
|
Typical Scan Tool Data
HO2S 1 or 2
Circuit
|
Short to Ground
|
Open
|
Short to Voltage
|
Operating Conditions: Engine operating
in Closed Loop
Parameter Normal Range:
50-1 050 mV
|
HO2S 1 or 2 Signal
|
0 mV
|
1 275 mV
|
1 275 mV
|
HO2S 1 or 2 Low Signal
|
-
|
1 275 mV
|
-
|
Circuit/System Description
The heated oxygen sensors (HO2S) are used for fuel control and
catalyst monitoring. Each HO2S compares the oxygen content of the
surrounding air with the oxygen content of the exhaust stream. When
the engine is started, the control module operates in an open loop
mode, ignoring the HO2S signal voltage while calculating the
air-to-fuel ratio. While the engine runs, the HO2S heats up and
begins to generate a voltage within a range of
0-1 275 mV. Once sufficient HO2S voltage fluctuation is
observed by the control module, closed loop is entered. The control
module uses the HO2S voltage to determine the air-to-fuel ratio. An
HO2S voltage that increases toward 1 000 mV indicates a
rich fuel mixture. An HO2S voltage that decreases toward 0 mV
indicates a lean fuel mixture.
The heating elements inside each HO2S heat the sensor to bring
the sensor up to operating conditions faster. This allows the
system to enter closed loop earlier and the control module to
calculate the air to fuel ratio sooner.
Conditions for Running the DTC
• |
DTCs P0030 00, P0036 00, P0106 00,
P0107 00, P0108 00, P0112 00, P0113 00,
P0117 00, P0118 00, P0121 00, P0122 00,
P0123 00, P0201 00, P0202 00, P0203 00,
P0204 00, P0443 00, and P2135 00 are not set. |
• |
The engine is operating. |
• |
The ignition voltage is between 10-18 V. |
• |
The fuel system is in closed loop. |
• |
The vehicle is not decelerating. |
• |
The DTCs run continuously when the above
conditions are met for 5 s. |
Conditions for Setting the DTC
P0131 00 or P0137 00
The engine control module (ECM) detects that the Heated Oxygen
Sensor (HO2S) voltage is less than 50 mV for greater than
38 s for DTC P0131 00 or 43 s for
DTC P0137 00.
P0132 00 or P0138 00
The ECM detects that the Heated Oxygen Sensor (HO2S) voltage is
greater than 1 050 mV for greater than 10 s.
Action Taken When the DTC Sets
DTCs P0131 00, P0132 00, P0137 00, and
P0138 00 are Type B DTCs.
Conditions for Clearing the DTC
DTCs P0131 00, P0132 00, P0137 00, and
P0138 00 are Type B DTCs.
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
- Clear the DTCs with a scan tool.
- 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
Note: All modules must be
powered down or misdiagnosis may result.
- Ignition OFF, disconnect the scan tool and wait
60 s to ensure all modules are powered down.
- Ignition OFF, disconnect the B52A Heated Oxygen
Sensor 1 or B52B Heated Oxygen Sensor 2 harness
connector.
- Ignition OFF, measure for less than 5 Ω between
B52A Heated Oxygen Sensor 1 or B52B Heated Oxygen
Sensor 2 low signal circuit terminal 3 and ground.
⇒ |
If more than the specified range, test the
appropriate B52A Heated Oxygen Sensor 1 or
B52B Heated Oxygen Sensor 2 low signal circuit for an
open/high resistance. If the circuit tests normal, replace the
K20 Engine Control Module. |
- Ignition ON, test for 1.5-2.1 V between the
B52A Heated Oxygen Sensor 1 or B52B Heated Oxygen
Sensor 2 signal circuit terminal 4 and ground.
⇒ |
If less than the specified range, test the signal
circuit for a short to ground or an open/high resistance. If the
circuit tests normal, replace the K20 Engine Control
Module. |
⇒ |
If greater than the specified range, test the
signal circuit for a short to voltage. If the circuit tests normal,
replace the K20 Engine Control Module. |
- Install a 3 A fused bridging wire between the
B52A Heated Oxygen Sensor 1 or B52B Heated Oxygen
Sensor 2 signal circuit terminal 3 and the low reference
circuit terminal 4 of the appropriate B52A Heated Oxygen
Sensor 1 or B52B Heated Oxygen Sensor 2. Engine
running, verify the scan tool HO2S 1 or HO2S 2 parameter
is less than 60 mV.
⇒ |
If greater than the specified value, replace the
K20 Engine Control Module. |
- Verify none of the following conditions exist:
• |
Water intrusion in the HO2S harness connector |
• |
Fuel saturation of the evaporative emission (EVAP)
canister |
• |
Exhaust leaks near the HO2S |
⇒ |
If you find any of the above conditions, repair as
necessary. |
- If all circuits test normal, replace the
B52A Heated Oxygen Sensor 1 or B52B Heated Oxygen
Sensor 2.
Repair Instructions
Caution: Refer to
Heated Oxygen Sensor Resistance Learn Reset
Caution in the Preface section.
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
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