Toyota Tundra. Manual — part 1519

Fig. 56: Identifying Terminals Of D33 Or D34 A/F Sensor Connector
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

b. Disconnect the D74 ECM connector.

c. Measure the resistance according to the value(s) in the table below.

Standard resistance

RESISTANCE SPECIFIED CONDITION

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to next step.

6. CHECK WHETHER DTC OUTPUT RECURS

a. Connect the Techstream to the DLC3.

b. Turn the ignition switch to ON.

c. Turn the Techstream ON.

d. Clear DTCs (see DTC CHECK/CLEAR ).

e. Start the engine.

f. Allow the engine to idle for 1 minute or more.

g. Enter the following menus: Powertrain/Engine and ECT/Trouble Codes.

h. Read DTCs.

Result

RESULT REFERENCE

B: REPLACE ECM (See REMOVAL )

A: CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT
PROBLEMS )

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); DTC P0141
OXYGEN SENSOR HEATER CIRCUIT MALFUNCTION (BANK 1 SENSOR 2); DTC P0161
OXYGEN SENSOR HEATER CIRCUIT MALFUNCTION (BANK 2 SENSOR 2)

DESCRIPTION

Refer to DTC P0136 .

HINT:

Tester Connection

Condition Specified Condition

D33-1 (HA1A) - D74-22 (HA1A)

Always

Below 1 ohms

D34-1 (HA2A) - D74-20 (HA2A)

Always

Below 1 ohms

D33-1 (HA1A) or D74-22 (HA1A) - Body ground Always

10 kohms or higher

D34-1 (HA2A) or D74-20 (HA2A) - Body ground Always

10 kohms or higher

Result

Proceed to

No DTC is output

A

P0031, P0032, P0051 or P0052 is output

B

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra



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.

Fig. 57: Oxygen Sensor Heater Control - Circuit Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

DTC DETECTION CONDITION AND TROUBLE AREA REFERENCE CHART

DTC

DTC Detection Condition

Trouble Area

P0037
P0057

The heater current is at the
specified value or less while the
heater is operating (1 trip
detection logic)



Open in HO2 sensor heater
circuit



HO2 sensor heater (for
Sensor 2)



Integration relay



ECM

P0038
P0058

Heated Oxygen (HO2) sensor
heater current more than 2 A (1
trip detection logic)



Short in HO2 sensor heater
circuit



HO2 sensor heater (for
Sensor 2)



Integration relay



ECM



Open or short in HO2 sensor

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

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 portion 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.

Heated oxygen sensor heater range check (P0037, P0038, P0057 and P0058):

The ECM monitors the current applied to the O2 sensor heater to check the heater for malfunctions. If the
current is below the threshold value, the ECM determines that there is an open circuit in the heater. If the
current is above the threshold value, the ECM determines that there is a short circuit in the heater.

The ECM constantly monitors the current applied to the heater. If the ECM detects an open or short circuit, the
ECM turns the MIL on and sets a DTC.

If a malfunction is detected, the ECM cuts off the current applied to the heater.

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.

Heated oxygen sensor heater performance (P0141 and P0161):

After the accumulated heater ON time exceeds 100 seconds, the ECM calculates the heater resistance using the
battery voltage and the current applied to the heater.

If the resistance is above the threshold value, the ECM determines that there is a malfunction in the HO2 sensor
heater and sets DTC P0141 or P0161.

P0141
P0161

Cumulative heater resistance
correction value exceeds threshold
(2 trip detection logic)

heater circuit



HO2 sensor heater (for
Sensor 2)



Integration relay



ECM

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra