P0161
2GR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0037,P0038,P0057,P0058,P0141,P0161: Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)
P0161 - Oxygen Sensor Heater Circuit Malfunction (Bank 2 Sensor 2)
DESCRIPTION
Refer to DTC P0136 P0136.
HINT
- 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 power 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.
HINT
- Bank 1 refers to the bank that includes the No. 1 cylinder.
- Bank 2 refers to the bank that does not include the 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.
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 will determine that there is an open circuit in the heater. If the current is above the threshold value, the ECM will determine that there is a short circuit in the heater.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
All:
P0037 and P0057:
P0038 and P0058 (Case 1):
P0038 and P0058 (Case 2):
P0141 and P0161:
TYPICAL MALFUNCTION THRESHOLDS
P0037 and P0057:
P0038 and P0058:
P0141 and P0161:
COMPONENT OPERATING RANGE
WIRING DIAGRAM
Refer to DTC P0136 P0136.
CONFIRMATION DRIVING PATTERN
These DTCs are detected when the engine idles for 110 seconds or more.
INSPECTION PROCEDURE
HINT
- Sensor 2 refers to the sensor mounted behind the Three-Way Catalytic Converter (TWC) and located far from the engine assembly.
- Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air-fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction Freeze Frame Data.
PROCEDURE
1. INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)
(a) Disconnect the K57 or K34 heated oxygen (HO2) sensor connectors.
(b) Measure the resistance of the HO2 sensor connector.
Standard resistance (Bank 1 sensor 2):
Standard resistance (Bank 2 sensor 2):
(c) Reconnect the HO2 sensor connector.
NG -- REPLACE HEATED OXYGEN SENSOR
OK -- Continue to next step.
2. CHECK TERMINAL VOLTAGE (+B OF HEATED OXYGEN SENSOR)
(a) Disconnect the K57 or K34 heated oxygen (HO2) sensor connectors.
(b) Turn the power switch off.
(c) Measure the voltage between the terminals of the K57 or K34 HO2 sensor connector and body ground.
Standard voltage (Bank 1 sensor 2):
Standard voltage (Bank 2 sensor 2):
(d) Reconnect the HO2 sensor connectors.
OK -- CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - ECM)
NG -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - EFI NO. 2 FUSE)
(a) Disconnect the K57 or K34 heated oxygen (HO2) sensor connectors.
(b) Remove the EFI NO. 2 fuse from the engine room No. 1 relay block.
(c) Measure the resistance.
Standard resistance (Check for open):
Standard resistance (Check for short):
(d) Reinstall the EFI NO. 2 fuse.
(e) Reconnect the HO2 sensor connectors.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- CHECK ECM POWER SOURCE CIRCUIT
4. CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - ECM)
(a) Disconnect the K57 or K34 heated oxygen (HO2) sensor connectors.
(b) Disconnect the E83 ECM connector.
(c) Measure the resistance.
Standard resistance (Check for open):
Standard resistance (Check for short):
(d) Reconnect the ECM connector.
(e) Reconnect the HO2 sensor connectors.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
5. CHECK WHETHER DTC OUTPUT RECURS
(a) Clear DTCs DTC Check / Clear.
(b) Put the engine in inspection mode Inspection Mode Procedure.
(c) Connect the Techstream to the DLC3.
(d) Turn the Techstream on.
(e) Allow the engine to idle for 2 minutes or more.
(f) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(g) Read the DTCs.
Result:
B -- REPLACE ECM Removal
A -- CHECK FOR INTERMITTENT PROBLEMS