P0130 - 02 Sensor Circuit Malfunction (Bank I Sensor 1)
OBD-II Trouble Code Technical Description02 Sensor Circuit Malfunction (Bank I Sensor 1)
What does that mean?The O2 sensor produces a voltage based on oxygen content in the exhaust. The voltage varies between .1 and .9 Volts, .1 indicating lean and .9 indicating rich. The ECM constantly monitors this voltage while in closed loop to determine how much fuel to inject. If the ECM determines that the O2 sensor voltage was too low (less than .4 Volts) for too long (for more than 20 seconds (time varies with model)), this code is set.
Potential SymptomsDepending if the problem is intermittent or not, there may be no symptoms other than MIL (malfunction indicator lamp) illumination. If the problem is constant, then symptoms may include one or more of the following:
Engine runs rough, missing or stumbling
Blows black smoke from tail pipe
Poor fuel economy
CausesUsually the cause of P0130 is a bad oxygen sensor, however this isn't always the case. If your o2 sensors haven't been replaced and they are old, it's a good bet that the sensor is the problem. But, It could be caused by any of the following:
Water or corrosion in the connector
Loose terminals in the connector
Wiring burnt on exhaust components
Open or short in the wiring due to rubbing on engine components
Holes in exhaust allowing unmetered oxygen into exhaust system
Unmetered vacuum leak at the engine
Bad o2 sensor
Possible SolutionsUsing a scan tool, determine if the Bank 1, sensor 1 is switching properly. It should switch rapidly between rich and lean, evenly.
1. If it does, the problem is likely intermittent and you should examine the wiring for any visible damage. Then perform a wiggle test by manipulating the connector and wiring while watching the o2 sensor voltage. If it drops out, fix the appropriate part of the wiring harness where problem resides.
2. If it doesn\'t switch properly, try to determine if the sensor is accurately reading the exhaust or not. Do this by removing the fuel pressure regulator vacuum supply briefly. The o2 sensor reading should go rich, reacting to the extra fuel added. Reinstall regulator supply. Then induce a lean condition by removing a vacuum supply line from the intake manifold. The o2 sensor reading should go lean, reacting to the enleaned exhaust. If the sensor operates properly, then the sensor may be okay and the problem may be holes in the exhaust or an unmetered vacuum leak in the engine (NOTE: Unmetered vacuum leaks at the engine are almost always accompanied by lean codes. Refer to the appropriate articles for diagnosing an unmetered vacuum leak). If the exhaust does have holes in it, it's possible that the o2 sensor may be misreading the exhaust because of the extra oxygen entering the pipe via those holes
3. If none of this is the case and the o2 sensor just isn't switching or acts sluggish, unplug the sensor and make sure there is 5 Volt reference voltage to the sensor. Then check for 12V supply to the o2 sensor's heater circuit. Also check for continuity to ground on the ground circuit. If any of these are missing, or aren't their proper voltage, repair open or short in the appropriate wire. The o2 sensor will not operate properly without proper voltage. If the proper voltages are present, replace the o2 sensor.
OBD-II Trouble Code Technical Description
Intake Air Temperature Circuit High Input
What does that mean?
The powertrain control module (PCM) monitors the temperature of the air entering the engine. The PCM supplies a 5 volt reference voltage to the Intake Air Temperature (IAT) sensor. The IAT is a thermistor that varies resistance based on temperature. As the temperature increases, resistance decreases. Low temperature results in a high signal voltage. When the PCM sees a signal voltage higher than 5 volts, it sets this P0113 check engine light code.
There will likely be no symptoms other than illumination of the Malfunction Indicator Lamp (MIL - Check Engine Light / Service Engine Soon).
A code P0113 may mean that one or more of the following has happened:
•Internally failed IAT sensor
• Faulty connection at IAT sensor
• Open in IAT ground circuit or signal circuit
• Short to voltage in IAT signal circuit or reference circuit
•IAT harness and/or wiring routed too close to high-voltage wiring (e.g. alternator, spark plug cables, etc.)
• Faulty PCM (less likely but not impossible)
First, if you have access to a scan tool, is there an IAT reading? If the IAT reading is logical then the problem is likely intermittent. If the reading is less than -30 degrees, unplug the connector. Install a jumper wire between the harness connector signal and ground circuits. The IAT temperature reading on the scan tool should be maxed out at the high end. For example it should be 280 degrees Farenheit or higher. If it is, the wiring is okay, and it may have been the connection. If it isn't install the jumper wire between the IAT signal circuit and the chassis ground.
If now the IAT reading on the scan tool is maxed out then check for an open in the IAT ground circuit. If you get no reading at all on the scan tool, it's likely that the sensor signal is open or the 5 volt reference is missing. Check using a DVOM (digital volt ohm meter) for a 5 volt reference. If it's there, then unplug the connector at the PCM and check for continuity on the IAT signal circuit between the PCM connector and the IAT connector.