O2 sensor heater DTC

[x Spades x]

Hey Fellas,

I'm trying to pass emissions for a road trip and I'm having trouble with the O2 sensor heater not readying up.

I just put two brand new pre cat sensors last night and a few drive cycles. Looks like O2 sensor is good, but the heater still not complying.

Hassan suppressed the secondary O2 sensor DTC (not new), would that have anything to do with it? It's been about 300 miles and I'm just lost.

Thanks in advance!!

[eacmen]

Are you sure the o2 sensor heaters are working? There is a fuse in the main ecu box specifically for o2 heaters.

[x Spades x]

Are you sure the o2 sensor heaters are working? There is a fuse in the main ecu box specifically for o2 heaters.

Thanks for the tip, i didn't know that.

The front two sensors (pre cat) are brand new from FCP Euro, those are whats being monitored correct? Not sure if it's there or the post cats.

[Altaran]

Thanks for the tip, i didn't know that.

The front two sensors (pre cat) are brand new from FCP Euro, those are whats being monitored correct? Not sure if it's there or the post cats.

The heaters are in all sensors. As far as I remember from converting mine to wideband, all four O2 sensors use the same fuse. At least I only deleted one fuse when I removed all factory sensor wiring.

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[x Spades x]

The heaters are in all sensors. As far as I remember from converting mine to wideband, all four O2 sensors use the same fuse. At least I only deleted one fuse when I removed all factory sensor wiring.

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Looks like all 5 fuses in the black ecu box are good. Ugh, I was hoping that was the issue. There should be no reason why it should take more that 10 miles for this to be ready. I'm at 400 miles at this point.

[Altaran]

Looks like all 5 fuses in the black ecu box are good. Ugh, I was hoping that was the issue. There should be no reason why it should take more that 10 miles for this to be ready. I'm at 400 miles at this point.

Best way is to check with Inpa, you can read lamda voltage and probe resistor for each of the four sensors. Then you can find what gives bad values and replace this.

The other thing you can do is check if the wiring harness is ok. All four connectors are under the plastic engine cover. Just use a multimeter to make sure power is being supplied.

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[sapote]

Hey Fellas,

I'm trying to pass emissions for a road trip and I'm having trouble with the O2 sensor heater not readying up.

All threads should include car production year/month, smg or manual, so people can get the right information.

It only says O2 heater not complete but we don't know the bypassed post cats or pre cat. You should use inpa to read the codes so we can narrow down to the root cause.

[sapote]

check the voltage on the 4 pin connector with engine running, for both precat sensors:

pin1 red/white wire to F4 fuse should be 12v
pin2 brown wire should be 0v or pwm switching between 12v and 0v, but should not be constant 12v.

Also do the same for the post cat as I am curious if they are bypassed with tuned DME.

[x Spades x]

All threads should include car production year/month, smg or manual, so people can get the right information.

It only says O2 heater not complete but we don't know the bypassed post cats or pre cat. You should use inpa to read the codes so we can narrow down to the root cause.

understood. I will do that for next time.

For now it's a 2005 ZCP, SMG... I think the tune suppresses post cat O2 sensors.

the pre cat sensors are 2 days old (Bosch). I've bought 2 sets of O2s before these new ones from Mparts, and still heaters weren't ready.

[PSUEng]

The post cat O2s are for emissions, the pre-cat O2s actually impact how your car runs. If any O2 heaters are too slow (light off time) then readings of exhaust gas stream NOX content, as a function of the catalyst properly working in the case of post cat O2s, will be off and DTCs set. DTCs also exist for voltage out of range and infinite resistance (and probably others I can't recall atm). I would agree with above advice that you should monitor O2 voltages if possible to confirm operation and/or check for disconnections at the harness as well as provide your hardware/software configuration. You could have a quite a few things going on here. On a side note, is your SAP deleted?

[x Spades x]

The post cat O2s are for emissions, the pre-cat O2s actually impact how your car runs. If any O2 heaters are too slow (light off time) then readings of exhaust gas stream NOX content, as a function of the catalyst properly working in the case of post cat O2s, will be off and DTCs set. DTCs also exist for voltage out of range and infinite resistance (and probably others I can't recall atm). I would agree with above advice that you should monitor O2 voltages if possible to confirm operation and/or check for disconnections at the harness as well as provide your hardware/software configuration. You could have a quite a few things going on here. On a side note, is your SAP deleted?

I will do. Checking everything today!

Yes, SAYess deleted. I kept the cold start on as well as the dtc. A warning light came on for sap. I deketed it and started a 2nd drive cycle. It readies up after another 2 cold starts this time without the SES light.

[Riley]

Oh man. I had this same issue last year with never setting o2 heaters. My tuner was able to fix it. Let me ask if he remembers what he did.

[eacmen]

Oh man. I had this same issue last year with never setting o2 heaters. My tuner was able to fix it. Let me ask if he remembers what he did.

If you still have the before and after bin files and they are not encrypted I can tell you what was changed.

[x Spades x]

Oh man. I had this same issue last year with never setting o2 heaters. My tuner was able to fix it. Let me ask if he remembers what he did.

I appreciate it, thank you!
I need to get this set within the next 2 or 3 days... desperation has set in! 😆 🤣

[eacmen]

I appreciate it, thank you!
I need to get this set within the next 2 or 3 days... desperation has set in! 😆 🤣

Just tape a $50 in front of the OBD port.