[Ron]

Need assistance. I am troubleshooting a p0030 and p0050 for o2 heater circuit on a 2011 Hyundai Genesis 4.6. I changed both o2 sensors with OEM. Swapped ECM to another cloned ECM. Replaced entire engine wiring harness, still have the codes. Before you say it, yes, I am shooting the parts cannon at it. I am a backyard mechanic. If I wanted.

To take it to the dealer, I would have already. Just looking for some constructive advice on what the problem with the car may be.

Note: I cannot find a wiring diagram online for my car.

[Eric]

You went way overboard with the parts cannon. What did you replace the O2 sensors with? Was it OEM or some cheapo O2 sensors?

Your ECM should not need to be swapped with anything. Put the original back in because that has nothing to do with your problem.

The issue has to do with the circuit.

[Ron]

The codes are saying that there is a circuit fault. Could be damaged or corroded connectors, or not.

The circuit fault is detected by the PCM by means of an expected load or resistance in the circuit. The o2 heater circuit is provided power through the PCM, o2 sensor has a heater element inside to insure it is brought up to temperature quickly. The fuel management system can then work to control mixture. The sensor will eventually reach operating temp because it is in the exhaust stream, but just after start up, it doesn’t produce a signal and the fuel mixture is approximated by air and coolant temperature. They call this open loop, when the PCM is in control and has a signal from the o2, that is closed loop.

Back to the heater element, when just started, the o2 and the element are cold, the element’s resistance is lower, and current draw is higher, loading the circuit more. As the element gets hotter, it’s resistance increases, circuit load decreases, thus controlling the heater element.

The PCM monitors all this, when values aren’t as expected, those codes appear. Since it is “seeing” only values, and they are not what is expected. It can only call a circuit error. It doesn’t know what is causing the unexpected readings. There is a troubleshooting block diagram for testing this. It is manufacturer/ vehicle specific, and requires use of a volt meter and the wiring diagram along with the troubleshooting >if/then< procedure.

It could be as some as a blown fuse or bad relay. Then again, it could be a faulty PCM. Without the diagnostic procedure and diagram, you will not know where to look or what to condemn.

[Cody]

Check fuses? Generally, a heater circuit has a fuse for it.

[David]

Might be cheaper to take it to a real mechanic.

[Oscar]

Have you thought of the possibility that you bought defective o2 sensors? If you didn’t buy oem and got some off the internet, it’s a big possibility, it’s even possible if you got them from autozone or whatever. Get a volt meter and test the sensors for resistance. I don’t remember off the top of my head, but I think in spec is between .40 and .70 resistance. You’ll have to look it up.

[Aaron]

Just the heater circuits? Find the two matching colors on the o2 sensor side of the harness. Most of the time, 2 white wires. Check for power with key on, cold start. If there’s power, disconnect and ohm across the 2 wires for an open. If it’s open circuit, o2 is bad. If there’s no power to heater wires, note the harness side colors, get a pinout of the computer and test at the PCM.

[Sean]

I checked the wiring diagram, check ENG SNSR 1 10A. Powers all the 02 sensors and the camshaft position sensors. That fuse gets power from the Engine Control Relay, which is powered by the ECU fuse 30A.

The signal is from ECM, which is a ground signal to enable the circuit.

On the sensor, BRN/ORG is signal, GRN is ground, PNK is heating from the ECM, BLK is B+ from that 10A fuse. Top fixes in ProDemand is the sensor or re-program the ECM.

If you need the actual diagrams, just send a PM.

[Author]

Posts