P0031
2GR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0031, P0032, P0051, P0052: Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1)
P0052 - Oxygen (A/F) Sensor Heater Control Circuit High (Bank 2 Sensor 1)
DESCRIPTION
Refer to DTC P2195 P2195.
HINT
- When any of these DTCs are set, the ECM enters fail-safe mode. The ECM turns off the A/F 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 A/F sensor heater circuit uses a relay on the +B side of the circuit.
MONITOR DESCRIPTION
- The ECM uses information from the Air-Fuel Ratio (A/F) sensor to regulate the air-fuel ratio and keep it close to the stoichiometric level. This maximizes the ability of the Three-Way Catalytic Converter (TWC) to purify the exhaust gases.
- The A/F sensor detects oxygen levels in the exhaust gas and transmits the information to the ECM. The inner surface of the sensor element is exposed to the outside air. The outer surface of the sensor element is exposed to the exhaust gas. The sensor element is made of platinum coated zirconia and includes an integrated heating element.
- The zirconia element generates a small voltage when there is a large difference in the oxygen concentrations between the exhaust gas and outside air. The platinum coating amplifies this voltage generation.
- The A/F sensor is more efficient when heated. When the exhaust gas temperature is low, the sensor cannot generate useful voltage signals without supplementary heating. The ECM regulates the supplementary heating using a duty-cycle approach to adjust the average current in the sensor heater element. If the heater current is outside the normal range, the signal transmitted by the A/F sensor will be inaccurate, as a result, the ECM will be unable to regulate air-fuel ratio properly.
- When the current in the A/F sensor heater is outside the normal operating range, the ECM interprets this as a malfunction in the sensor heater and sets a DTC.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
All:
P0031 and P0051:
P0032 and P0052:
TYPICAL MALFUNCTION THRESHOLDS
P0031 and P0051:
P0032 and P0052:
COMPONENT OPERATING RANGE
P0031 and P0051:
P0032 and P0052:
WIRING DIAGRAM
Refer to DTC P2195 P2195.
INSPECTION PROCEDURE
NOTICE:
Inspect the fuses of circuits related to this system before performing the following inspection procedure.
HINT
- Although the DTC titles include 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.
- 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.
- 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 AIR FUEL RATIO SENSOR (HEATER RESISTANCE)
(a) Disconnect the E74 or E70 A/F sensor connector.
(b) Measure the resistance of the A/F sensor connector.
Standard resistance (Bank 1 sensor 1):
Standard resistance (Bank 2 sensor 1):
(c) Reconnect the A/F sensor connector.
NG -- REPLACE AIR FUEL RATIO SENSOR
OK -- Continue to next step.
2. CHECK TERMINAL VOLTAGE (+B OF A/F SENSOR)
(a) Disconnect the E74 or E70 A/F sensor connector.
(b) Turn the power switch on (IG).
(c) Measure the voltage between the terminals of the E74 or E70 A/F sensor connector and body ground.
Standard voltage (Bank 1 sensor 1):
Standard voltage (Bank 2 sensor 1):
(d) Reconnect the A/F sensor connector.
OK -- CHECK HARNESS AND CONNECTOR (A/F SENSOR - ECM)
NG -- Continue to next step.
3. INSPECT INTEGRATION NO.2 RELAY (A/F RELAY)
(a) Inspect the integration No. 2 relay (A/F relay) Testing and Inspection.
NG -- REPLACE INTEGRATION NO.2 RELAY
OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (A/F SENSOR - INTEGRATION NO. 2 RELAY)
4. CHECK HARNESS AND CONNECTOR (A/F SENSOR - ECM)
(a) Disconnect the E74 or E70 A/F sensor connector.
(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 A/F sensor connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
5. CHECK DTC OUTPUT
(a) Clear the 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 1 minute 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