99 Boxster Check engine light issue ( Not Normal)

[JFP in PA]

Both codes indicate that the current to the heated O2 sensors on both engine banks is not where it should be. These are typically not a sensor or relay issue, are most commonly a wiring issue; namely high resistance or an interruption of either the heater circuit or sensor wiring. Diagnostic tree in the OBD II manual is to test the sensor (always the first step), then start testing the wiring harness heading to the DME

This is why swapping parts did not fix it, there was probably nothing wrong with the original sensors. the final step in the diagnostic tree says it all, "Repair wiring harness."

[porscherescuer]

Thanks JFP. That's what I'm thinking too. I appreciate the advice. Has anyone had a similar problem from their 99 Box?

[Topless]

Originally Posted by JFP in PA

Both codes indicate that the current to the heated O2 sensors on both engine banks is not where it should be. These are typically not a sensor or relay issue, are most commonly a wiring issue; namely high resistance or an interruption of either the heater circuit or sensor wiring. Diagnostic tree in the OBD II manual is to test the sensor (always the first step), then start testing the wiring harness heading to the DME

This is why swapping parts did not fix it, there was probably nothing wrong with the original sensors. the final step in the diagnostic tree says it all, "Repair wiring harness."

+1
Sounds like a failed harness or faulty heating circuit on the new O2 sensors... it happens:

P1117 and P1121
1. Remove connector of 02 sensor 1/2 after catalytic converter.
2. Connect ohmmeter on pin side to pins 1 and 2.
Display: 1.8 - 2.5 ohms at 20°C.
3. Connect ohmmeter on pin side to pin 1 and 02 sensor housing.
Display: infinite ohms

[porscherescuer]

I will try that tomorrow topless. I appreciate the advice. Does anyone know how hard the harness is to replace. Or how much one costs?

[JFP in PA]

Replacing the harness is not the way you want to go, besides being ridiculously expensive, it is not necessary to do the repair. If some wiring is damaged, you just replace that section of wire with aftermarket equivalent materials.

[porscherescuer]

I took a look at the dme and all the wiring in the trunk. Everything looks perfect. Hmm, maybe my mechanic can find something I can't. I will be sure to update once I find something.

[JFP in PA]

You need to be testing continuity and resistance on the specific wires used by each of the sensor heaters; looking at the wire bundles will not tell you much of anything……

[porscherescuer]

I don't know that much about testing continuity and definitely don't have the tools to test this. I am taking it to the shop on Wednesday and will let you know what I find out. Thanks again for the suggestions everyone.