Toyota Tundra. Manual — part 1243

B : REPLACE ECM (See REMOVAL )

A : END

DTC P2237 OXYGEN (A/F) SENSOR PUMPING CURRENT CIRCUIT/OPEN (BANK 1 SENSOR 1);
DTC P2238 OXYGEN (A/F) SENSOR PUMPING CURRENT CIRCUIT LOW (BANK 1 SENSOR 1);
DTC P2239 OXYGEN (A/F) SENSOR PUMPING CURRENT CIRCUIT HIGH (BANK 1 SENSOR 1);
DTC P2240 OXYGEN (A/F) SENSOR PUMPING CURRENT CIRCUIT/OPEN (BANK 2 SENSOR 1);
DTC P2241 OXYGEN (A/F) SENSOR PUMPING CURRENT CIRCUIT LOW (BANK 2 SENSOR 1);
DTC P2242 OXYGEN (A/F) SENSOR PUMPING CURRENT CIRCUIT HIGH (BANK 2 SENSOR 1);
DTC P2252 OXYGEN (A/F) SENSOR REFERENCE GROUND CIRCUIT LOW (BANK 1 SENSOR 1);
DTC P2253 OXYGEN (A/F) SENSOR REFERENCE GROUND CIRCUIT HIGH (BANK 1 SENSOR 1);
DTC P2255 OXYGEN (A/F) SENSOR REFERENCE GROUND CIRCUIT LOW (BANK 2 SENSOR 1);
DTC P2256 OXYGEN (A/F) SENSOR REFERENCE GROUND CIRCUIT HIGH (BANK 2 SENSOR 1)

DESCRIPTION

HINT:



Although the DTC titles say oxygen sensor, these DTCs relate to the Air-Fuel Ratio (A/F) sensor.



Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located
near the engine assembly.

The A/F sensor, which is located between the exhaust manifold and catalyst, consists of alloyed metal elements
and a heater.

Depending on the engine operating conditions, the heater heats the sensor elements to activate them. Battery
voltage is applied to the heater, the sensor ground is controlled by the ECM using a duty ratio. The sensor
elements convert the oxygen concentration in the exhaust gas into voltage values to output. Based on the
voltage, the ECM determines the air-fuel ratio and regulates the fuel injection volume depending on the air-fuel
ratio and engine operating conditions. The voltage changes between 0.6 V and 4.5 V while the engine is
running. If the air-fuel ratio is lean, which means the oxygen concentration in the exhaust gas is high, the
voltage is high. If the air-fuel ratio is rich, which means the oxygen concentration in the exhaust gas is low, the
voltage is low.

P2195, P2196, P2197 or P2198 (A/F sensor pending DTCs)

B

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

Fig. 206: Oxygen (A/F) Sensor Pumping Current Circuit / Open (Bank 1 Sensor 1) - Circuit Diagram

Fig. 207: Air-Fuel Ratio Graph

DTC TROUBLE DETECTION CONDITION CHART

DTC

No.

DTC Detection Condition

Trouble Area

P2237
P2240

Open in the circuit between terminals A1A+ and A1A-/ A2A+
and A2A- of the AF sensor while engine is running (2 trip
detection logic)



Open in A/F sensor
(bank 1,2 sensor 1)
circuit



A/F sensor (bank 1, 2

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

MONITOR DESCRIPTION

These DTCs are output when there is an open or short in the A/F sensor circuit, or if A/F sensor output drops.
To detect these problems, the voltage of the A/F sensor is monitored when turning the ignition switch to the ON
position, and the admittance (admittance is an electrical term that indicates the ease of flow of current) is
checked while driving. If the voltage of the A/F sensor is between 0.6 V and 4.5 V, it is considered normal. If
the voltage is out of the specified range, or the admittance is less than the standard value, the ECM will
determine that there is a malfunction in the A/F sensor. If the same malfunction is detected in next driving
cycle, the MIL will be illuminated and a DTC will be stored.

MONITOR STRATEGY

MONITOR STRATEGY

sensor 1)



ECM

P2238
P2241

Any of the following conditions are met (2 trip detection logic)



AF sensor output drops while engine is running.



Voltage at terminal A1A+/A2A+ is 0.5 V or less.



Voltage difference between terminals A1A+ and A1A-
/A2A+ and A2A- is 0.1 V or less.



Open or short in A/F
sensor (bank 1, 2 sensor
1) circuit



A/F sensor (bank 1, 2
sensor 1)



ECM

P2239
P2242

A1A+/A2A+ voltage more than 4.5 V (2 trip detection logic)



Open or short in A/F
sensor (bank 1, 2 sensor
1) circuit



A/F sensor (bank 1, 2
sensor 1)



ECM

P2252
P2255

A1A-/A2A- voltage 0.5 V or less (2 trip detection logic)



Open or short in A/F
sensor (bank 1, 2 sensor
1) circuit



A/F sensor (bank 1, 2
sensor 1)



ECM

P2253
P2256

A1A-/A2A- voltage more than 4.5 V (2 trip detection logic)



Open or short in A/F
sensor (bank 1, 2 sensor
1) circuit



A/F sensor (bank 1, 2
sensor 1)



ECM

P2237: A/F sensor (bank 1) open circuit between A1A+ and
A1A-
P2238: A/F sensor (bank 1) short circuit between A1A+ and

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

TYPICAL ENABLING CONDITIONS

TYPICAL ENABLING CONDITIONS

P2237 and P2240 (A/F sensor open circuit between A1A+ and A1A-/A2A+ and A2A-)

TYPICAL ENABLING CONDITIONS

Related DTCs

A1A-
P2238: A/F sensor (bank 1) short circuit between A1A+ and
GND
P2238: A/F sensor (bank 1) low impedance
P2239: A/F sensor (bank 1) short circuit between A1A+ and +B
P2240: A/F sensor (bank 2) open circuit between A2A+ and
A2A-
P2241: A/F sensor (bank 2) short circuit between A2A+ and
A2A-
P2241: A/F sensor (bank 2) short circuit between A2A+ and
GND
P2241: A/F sensor (bank 2) low impedance
P2242: A/F sensor (bank 2) short circuit between A2A+ and +B
P2252: A/F sensor (bank 1) short circuit between A1A- and GND
P2253: A/F sensor (bank 1) short circuit between A1A- and +B
P2255: A/F sensor (bank 2) short circuit between A2A- and GND
P2256: A/F sensor (bank 2) short circuit between A2A- and +B

Required Sensors/Components (Main) A/F sensor
Required Sensors/Components
(Related)

Engine Coolant Temperature (ECT) sensor, Crankshaft position
sensor

Frequency of Operation

Continuous

Duration

10 seconds

MIL Operation

2 driving cycles

Sequence of Operation

None

Monitor runs whenever following DTCs are not present

P0031, P0032 (A/F sensor heater - Sensor 1)
P0102, P0103 (MAF meter)
P0110, P0112, P0113 (IAT sensor)
P0115 - P0118 (ECT sensor)
P0120 - P0223, P2135 (TP sensor)
P0125 (Insufficient ECT for Closed Loop)
P0171, P0172 (Fuel trim)
P0300 - P0306 (Misfire)
P0335 (CKP sensor)
P0340 (VVT sensor)
P0441 - P0456, P2401 - P2420 (EVAP system)
P0500 (VSS)

Estimated sensor temperature

450 to 550°C (842 to 1022°F)

Engine

Running

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra