Toyota Tundra. Manual — part 1417
Fig. 217: Oxygen (A/F) Sensor Voltage Graph
DTC DETECTION CONDITION AND TROUBLE AREA
DTC
Code
DTC Detection Condition
Trouble Area
P2195
P2197
Conditions (a) and (b) continue for 5 seconds or more (2 trip
detection logic):
a. A/F sensor voltage more than 3.8 V for 5 seconds
b. Heated Oxygen (HO2) sensor voltage 0.21 V or higher
Open or short in A/F
sensor (for sensor 1)
circuit
A/F sensor (for sensor 1)
A/F sensor heater (for
sensor 1)
Integration relay
A/F sensor heater and
integration relay circuits
Air induction system
Fuel pressure
Injector
ECM
While fuel-cut operation performed (during vehicle
deceleration), A/F sensor current 3.6 mA or higher for 3
seconds (2 trip detection logic)
A/F sensor
ECM
Open or short in A/F
sensor (for sensor 1)
circuit
A/F sensor (for sensor 1)
2008 Toyota Tundra
2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra
HINT:
DTCs P2195 and P2196 indicate malfunctions related to bank 1 A/F sensor circuit.
DTCs P2197 and P2198 indicate malfunctions related to bank 2 A/F sensor circuit.
Bank 1 refers to the bank that includes No. 1 cylinder.
Bank 2 refers to the bank that includes No. 2 cylinder.
When either of these DTCs is set, check the A/F sensor output voltage by entering the following menus:
Powertrain/Engine and ECT/Data List/A/F Control System/AFS B1 S1 or AFS B2 S1.
Short-term fuel trim values can also be read using the Techstream.
The ECM regulates the voltages at the A1A+ and A1 A- or A2A+ and A2A- terminals of the ECM to a
constant level. Therefore, the A/F sensor output voltage cannot be confirmed without using the
Techstream.
If the A/F sensor is malfunctioning, the ECM sets the DTC P2195, P2196, P2197 or P2198.
MONITOR DESCRIPTION
Sensor voltage detection monitor
Under the air-fuel ratio feedback control, if the A/F sensor output voltage indicates rich or lean for a certain
period of time, the ECM determines that there is a malfunction in the A/F sensor. The ECM illuminates the MIL
and sets a DTC.
Example:
If the A/F sensor output voltage is less than 2.8 V (very rich condition) for 5 seconds, despite the rear HO2
sensor output voltage being less than 0.59 V, the ECM sets DTC P2196 or P2198. Alternatively, if the A/F
sensor output voltage is more than 3.8 V (very lean condition) for 5 seconds despite the rear HO2 sensor output
voltage being 0.21 V or higher, DTC P2195 or P2197 is set.
Sensor current detection monitor
P2196
P2198
Conditions (a) and (b) continue for 5 seconds or more (2 trip
detection logic):
a. A/F sensor voltage less than 2.8 V for 5 seconds
b. HO2 sensor voltage less than 0.59 V
A/F sensor heater (for
sensor 1)
Integration relay
A/F sensor heater and
integration relay circuits
Air induction system
Fuel pressure
Injector
ECM
While fuel-cut operation performed (during vehicle
deceleration), A/F sensor current less than 1.4 mA for 3
seconds (2 trip detection logic)
A/F sensor
ECM
2008 Toyota Tundra
2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra
A rich air-fuel mixture causes a low A/F sensor current, and a lean air-fuel mixture causes a high A/F sensor
current. Therefore, the sensor output becomes low during acceleration, and it becomes high during deceleration
with the throttle valve fully closed. The ECM monitors the A/F sensor current during fuel-cut and detects any
abnormal current values.
If the A/F sensor output is 3.6 mA or higher for more than 3 seconds of cumulative time, the ECM interprets
this as a malfunction in the A/F sensor and sets DTC P2195 or P2197 (high-side stuck). If the A/F sensor output
is less than 1.4 mA for more than 3 seconds of cumulative time, the ECM sets DTC P2196 or P2198 (low-side
stuck).
Fig. 218: A/F Sensor Current Monitor - Normal & Abnormal Sensor Output Graph
MONITOR STRATEGY
MONITOR STRATEGY
Related DTCs
P2195: A/F sensor signal stuck lean (bank 1)
P2196: A/F sensor signal stuck rich (bank 1)
P2197: A/F sensor signal stuck lean (bank 2)
P2198: A/F sensor signal stuck rich (bank 2)
Required Sensors/Components (Main)
A/F sensor
Required Sensors/Components (Related)
HO2 sensor
Frequency of Operation
Continuous
Duration
5 seconds: Sensor voltage detection monitor
3 seconds: Sensor current detection monitor
MIL Operation
2 driving cycles
2008 Toyota Tundra
2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra
TYPICAL ENABLING CONDITIONS
All
TYPICAL ENABLING CONDITIONS - ALL
Sensor voltage detection monitor:
TYPICAL ENABLING CONDITIONS - SENSOR VOLTAGE DETECTION MONITOR
Sensor current detection monitor:
TYPICAL ENABLING CONDITIONS - SENSOR CURRENT DETECTION MONITOR
TYPICAL MALFUNCTION THRESHOLDS
Sensor voltage detection monitor (Lean side malfunction P2195 and P2197):
Sequence of Operation
None
Monitor runs whenever following DTCs not
present
P0031, P0032, P0051, P0052 (A/F Sensor Heater -
Sensor 1)
P0037, P0038, P0057, P0058 (O2 Sensor Heater -
Sensor 2)
P0102 - P0103 (MAF meter)
P0110 - P0113 (IAT sensor)
P0115 - P0118 (ECT sensor)
P0120 - P0223, P2135 (TP sensor)
P0125 (Insufficient ECT for Closed Loop)
P0136, P0156 (O2 Sensor - Sensor 2)
P0171, P0172 (Fuel system)
P0300 - P0308 (Misfire)
P0335 (CKP sensor)
P0455, P0456 (EVAP system)
P0500 (VSS)
P2440 (AIR control valve stuck open)
P2441 (AIR control valve stuck close)
P2444 (AIP stuck On)
P2445 (AIP stuck Off)
Time after engine start
30 seconds or more
Fuel system status
Closed-loop
Battery voltage
11 V or higher
Atmospheric pressure
76 kPa (570 mmHg) or more
A/F sensor status
Activated
Continuous time of fuel cut
3 to 10 seconds
ECT
75°C (167°F) or more
2008 Toyota Tundra
2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra
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