Technical Description of OBD-II Trouble Code
Generic: Control Circuit for HO2S Heater (Bank 1 Sensor 1)
GM: Conditions for HO2S Heater Control Circuit
What does that signify?
This diagnostic trouble code (DTC) is a generic powertrain code that applies to OBD-II equipped vehicles, such as Toyota, VW, Ford, Dodge, Honda, Chevrolet, Hyundai, Audi, Acura, etc. The specific repair steps may vary depending on the model.
In order for an engine to function properly, there must be a precise air:fuel ratio of 14.7:1. To achieve this, the ECM (Engine control module) relies on the Heated Oxygen sensors (HO2S). The HO2S sensors detect the oxygen content in the exhaust.
This information is then transmitted to the ECM, which uses it to adjust the fuel delivery to the engine. A Heated Oxygen sensor contains a dedicated circuit that operates a heater, which warms up the Oxygen sensor faster than the exhaust gases. This reduces the time needed for the engine to achieve closed loop operation, resulting in decreased emissions.
In some vehicles, the O2 sensor heater receives a 12V fused supply voltage and a computer-controlled ground. The 12V supply voltage is provided to the heater whenever the key is in the on position. The computer activates the heater under certain conditions by completing the ground connection to the oxygen sensor heater. In other vehicles, the O2 sensor heater may receive a computer-controlled 12 volts feed and a continuous ground. If the ECM detects a fault in the Bank 1, sensor 1 heater circuit, a P0030 code may be set.
Symptoms
The symptoms of a P0030 DTC may include:
Causes
Potential causes of a P0030 trouble code may include:
Possible Solutions
Many times, a HO2 sensor’s heater element may go bad due to age or impact. Keep this in mind during your inspection. Perform a visual inspection of the Bank 1,1 O2 sensor. Repair any damaged wiring that has come into contact with the exhaust.
If the HO2 Sensor itself appears to be damaged, replace it. If a visual inspection reveals no obvious problems, viewing the faulty heater circuit on a scan tool may indicate if the fault is currently occurring. If the scan tool datastream shows that the Bank 1,1 heater element is pulling 0 amps, suspect an open in the circuit. Check for blown fuses and then disconnect the O2 sensor connector.
With the key on and the engine off, use a voltmeter to check for a 12-volt fused battery feed to the heater element. If there is no voltage present, repair any open or short in the B+ feed circuit, remembering to replace any blown fuse caused by the short. If the B+ battery feed is intact, remove the ground (control) circuit from the ECM wiring connector and check for resistance on the circuit. If there is infinite resistance, repair any open in the circuit. If the control circuit checks out, suspect a faulty O2 sensor. Replace it and re-check.
