Last Modified: 4-30-2014 6.6 C Doc ID: RM000000PFA00IX
Model Year: 2006 Model: LX470 Prod Date Range: [05/2005 -           ]
Title: 2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0037,P0038,P0057,P0058; Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2); 2006 MY LX470 [05/2005 -        ]

DTC

P0037

Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)

DTC

P0038

Oxygen Sensor Heater Control Circuit High (Bank 1 Sensor 2)

DTC

P0057

Oxygen Sensor Heater Control Circuit Low (Bank 2 Sensor 2)

DTC

P0058

Oxygen Sensor Heater Control Circuit High (Bank 2 Sensor 2)

DESCRIPTION

  • Refer to DTC P0136 2006 MY LX470 [05/2005 -        ]; 2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0136-P0138,P0156-P0158; Oxygen Sensor Circuit Malfunction (Bank 1 Sensor 2)+ .

HINT:

  • Sensor 2 refers to the sensor mounted behind the Three-Way Catalytic Converter (TWC) and located far from the engine assembly.
  • When any of these DTCs are set, the ECM enters fail-safe mode. The ECM turns off the Heated Oxygen (HO2) Sensor heater in fail-safe mode. Fail-safe mode continues until the ignition switch is turned OFF.
  • The ECM provides a pulse width modulated control circuit to adjust the current through the heater. The HO2 sensor heater circuit uses a relay on the +B side of the circuit.

DTC No.

DTC Detection Condition

Trouble Area

P0037

P0057

Heated Oxygen (HO2) sensor heater current less than 0.3 A (1 trip detection logic)
  • Open in Heated Oxygen (HO2) sensor heater circuit
  • Heated Oxygen (HO2) sensor heater
  • EFI Relay
  • ECM

P0038

P0058

Heated Oxygen (HO2) sensor heater current more than 2.0 A (1 trip detection logic)
  • Short in HO2 sensor heater circuit
  • HO2 sensor heater
  • EFI Relay
  • ECM

HINT:

  • Bank 1 refers to the bank that includes No. 1 cylinder.
  • Bank 2 refers to the bank that does not include No. 1 cylinder.
  • Sensor 1 refers to the sensor closest to the engine assembly.
  • Sensor 2 refers to the sensor farthest away from the engine assembly.

MONITOR DESCRIPTION

  • The sensing position of the Heated Oxygen (HO2) sensor has a zirconia element which is used to detect the oxygen concentration in the exhaust gas. If the zirconia element is at the appropriate temperature, and the difference between the oxygen concentrations surrounding the inside and outside surfaces of the sensor is large, the zirconia element generates voltage signals. In order to increase the oxygen concentration detecting capacity of the zirconia element, the ECM supplements the heat from the exhaust with heat from a heating element inside the sensor. When the current in the sensor heater is outside the standard operating range, the ECM interprets this as a malfunction in the sensor heater and sets a DTC.
  • Example:
  • The ECM sets DTC P0038 or P0058 when the current in the HO2 sensor heater is more than 2 A. Conversely, when the heater current is less than 0.3 A, DTC P0037 or P0057 is set.

MONITOR STRATEGY

Related DTCs

P0037: Heated oxygen sensor heater (bank 1) range check (low current)

P0038: Heated oxygen sensor heater (bank 1) range check (high current)

P0057: Heated oxygen sensor heater (bank 2) range check (low current)

P0058: Heated oxygen sensor heater (bank 2) range check (high current)

Required sensors / components

Heated oxygen sensor heater (bank 1 and 2)

Required sensors / components

Vehicle speed sensor

Frequency of operation

Continuous

Duration

P0037 and P0057: 0.5 seconds

P0038 and P0058: 0.3 seconds

MIL operation

Immediate

Sequence of operation

None

TYPICAL ENABLING CONDITIONS

All:

Battery voltage

10.5 V or more

Engine

Running

Starter

OFF

Catalyst intrusive monitoring

Not operating

Intrusive heating

Not operating

P0037 and P0057 (Low current):

When the following conditions are met

0.5 sec. or more

(a) Following conditions are met

-

Learned heater current during heater OFF

Completed

Intrusive heating

Not operating

Heating is OFF

Less than 0.1 seconds

Heater current

Less than 0.3 A

Intrusive heating for high current monitor

Not operating

(b) Following condition is met

-

Time after heaters are OFF

1 second or or more

P0038 and P0058 (High current):

When the following conditions are met

0.3 sec. or more

(a) Following conditions are met

-

Learned heater current during heater OFF

Completed

Intrusive heating

Not operating

Heating is OFF

Less than 0.1 second

Heater current

2 A or more

(b) Following condition is met

-

Time after heaters are OFF

1 second or or more

TYPICAL MALFUNCTION THRESHOLDS

P0037 and P0057 (Low current):

Following conditions are met

-

Heater

ON

Heater current

Less than 0.3 A

Intrusive heating

Operating

P0038 and P0058 (High current):

Either A or B is met

-

A. Following conditions are met

With intrusive heating

Heater

ON

Heater current

2 A or more

B. Following conditions are met

Without intrusive heating

Intrusive heating of learned heater current

Operating

Learned heater current during heater OFF

Operating

Heater current

More than 2 A

COMPONENT OPERATING RANGE

Heated Oxygen (HO2) sensor heater current

0.4 to 1 A (when engine idles, HO2 sensor warmed up and battery voltage 11 to 14 V)

MONITOR RESULT

  • Detailed information on Checking Monitor Status 2006 MY LX470 [05/2005 -        ]; 2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: CHECKING MONITOR STATUS .

The test value and test limit information are in the following table. Check the monitor result and test values after performing the monitor drive pattern (refer to "Confirmation Monitor").

  • Monitor Identification Date (MID) is assigned to each emission-related component.
  • Test Identification Date (TID) is assigned to each emission-related component.
  • Scaling is used to calculate the test value indicated on generic OBD II scan tools.

Heated oxygen sensor heater (Bank 1 sensor 2):

MID

TID

Scaling

Description of Test Value

Minimum Test Limit

Maximum Test Limit

$42

$90

Multiply by 0.001 (A)

Maximum sensor heater current

Minimum test limit

Maximum test limit

Heated oxygen sensor heater (Bank 2 sensor 2):

MID

TID

Scaling

Description of Test Value

Minimum Test Limit

Maximum Test Limit

$46

$90

Multiply by 0.001 (A)

Maximum sensor heater current

Minimum test limit

Maximum test limit

WIRING DIAGRAM

Refer to DTC P0136 2006 MY LX470 [05/2005 -        ]; 2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0136-P0138,P0156-P0158; Oxygen Sensor Circuit Malfunction (Bank 1 Sensor 2)+ .

INSPECTION PROCEDURE

HINT:

  • If other DTCs relating to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.
  • Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

1.

INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)

(a) Disconnect the H8 or H17 Heated Oxygen (HO2) sensor connectors.

(b) Measure the resistance of the HO2 sensor connector.

Standard resistance (Bank 1, 2 sensor 2):

Tester Connection

Specified Condition

HT (1) - +B (2)

11 to 16 Ω at 20°C (68°F)

HT (1) - E1 (4)

10 kΩ or higher

(c) Reconnect the HO2 sensor connector.
NG

REPLACE HEATED OXYGEN SENSOR

OK

2.

INSPECT EFI RELAY (Marking: EFI OR ECD)

(a) Remove the EFI relay from the engine room relay block.

(b) Measure the resistance of the EFI relay.

Standard resistance:

Terminal Connection

Specified Condition

1 - 3

10 kΩ or higher

1 - 3

Below 1 Ω

(when battery voltage applied to terminals 2 and 4)

(c) Reinstall the EFI relay.
NG

REPLACE EFI RELAY

OK

3.

INSPECT ECM (HT1B OR HT2B VOLTAGE)

(a) Turn the ignition switch ON.

(b) Measure the voltage of the E6, E7 and E8 ECM connectors.

Standard resistance:

Terminal Connection

Specified Condition

E8-1 (HT1B) - E6-1 (E1)

9 to 14 V

E7-5 (HT2B) - E6-1 (E1)

9 to 14 V

HINT:

  • The HT1B means the heated oxygen sensor bank 1 sensor 2.
  • The HT2B means the heated oxygen sensor bank 2 sensor 2.
OK

REPLACE ECM

NG

4.

CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - EFI RELAY)

(a) Check harness and connector 2006 MY LX470 [05/2005 -        ]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: ELECTRONIC CIRCUIT INSPECTION PROCEDURE .

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

5.

CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - ECM)

(a) Check harness and connector 2006 MY LX470 [05/2005 -        ]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: ELECTRONIC CIRCUIT INSPECTION PROCEDURE .

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

REPLACE ECM