CAR OBD CODES
OBD/DTC Search, e.g.P0146
CAR OBD CODES P0146
P0146 OBD Code Definition:
P0146 O2 Sensor Circuit No Activity Detected Bank 1 Sensor 3
P0146 OBD Code Description:
OBD2 Code P0146 Definition:
The catalytic converter is used to control emissions. The o2 sensor on Bank 1, position 3 is aft of the converter and monitors the catalyst efficiency. The PCM (Powertrain Control Module) does this by comparing the post-cat o2 sensor to the pre-cat o2 sensors. The o2 sensor is a four wire sensor. The PCM supplies a reference to the sensor of about half a volt and also supplies a sensor ground and 12 volts for the heater element. The fourth wire is a ground for the heater element (the heater in the sensor helps the sensor to warm up faster which allows the engine to reach closed loop sooner). The sensor varies the supplied reference voltage based on oxygen content of the exhaust. Oxygen sensors are capable of varying between 0.1 volts to 0.9 volts. Lean exhaust produces low voltage and causes the supplied 0.45 volts to drop. Rich exhaust produces high voltage and causes the supplied 0.45 voltage to increase. Pre-catalyst o2 sensors switch between low and high voltage rapidly. However a post-cat o2 sensor may switch much slower & not vary as much (this is normal). If the sensor doesn’t respond as it should or there are too few switches in a given time period, P0146 may set.
Symptoms
Possible sumptoms of P0146
Symptoms of a P0146 DTC may include: MIL (Malfunction Indicator Lamp) on May idle or drive poorly Fuel economy may decrease
Possible Causes
Possible causes of P0146
Potential causes of an P0146 code include: Bad Bank 1, position 3, o2 sensor Wiring problem, melted harness, broken connectors, etc. Bad PCM
Possible Solutions
1. Start the engine and allow it to reach operating temperature. Using a scan tool, observe the Bank 1 position 3 o2 sensor. If it isn’t moving between 0.1 and 0.9 volts, increase the engine RPM to a fast idle and then recheck the sensor voltage reading. If it starts switching now, the sensor may be sluggish and/or intermittently going “dormant”. Replacing the sensor at this point would be a good idea. Visually check the o2 sensor for contaminates, etc. If you suspect it’s contaminated with coolant or oil, replace it. a. But, if it still isn’t responding after increasing engine RPM, turn off the engine and unplug the 1/3 o2 sensor. With KOEO (key on engine off) check that there is battery voltage and ground to the o2 sensor heater element. If the heater element has no battery voltage it can cause the o2 sensor to go “dormant” and not switch properly which can cause a P0146. So, diagnose that problem first(there will usually be other codes present). b. If there is power and ground to the heater element check that the sensor ground is present. If it is, connect a jumper wire between the sensor ground and signal wire. Now the 1/3 o2 sensor reading should be low. If so, replace the Bank 1 position 3 o2 sensor. c. If, after connecting the jumper wire, the o2 sensor reading still remains “stuck”, check for wiring problems, harness contacting exhaust components, or broken connectors. Repair as necessary. Then recheck. d. If you can find no wiring problems and the o2 sensor reading on the scan tool doesn’t change after installing the jumper wire, recheck at the PCM connector. If it still shows no change, the PCM may be at fault.
Note: The information on the P0146 error code is purely informative, if you need more useful information, please consult your technician.
B1C21 P0B1F B1370 B19AA B2B0E B1930 B2971 B2936 B1589 B1447 B007D B1841 B2051 B1470 B2060 OBDII Chassis Codes
C1825 C1B19 C1A01 C1908 C2000 C1146 C1776 C0021 C1837 C2792 C1780 C1111 C1979 C1282 C0324 OBDII Network Codes
U2474 U300A U1197 U0066 U0412 U1238 U0041 U0026 U1020 U0086 U0232 U0018 U0047 U0433 U0218 OBDII Powertrain Codes
P20A7 P0616 P001B P1292 P0070 P0546 P047B P067A P00AD P1A10 P3411 P0114 P0627 P0409 P1801