Code P1130, P1128 and P0134
 

Hello everyone,

I have a base 2002 Porsche Boxster which I purchased about 6 months ago. the vehicle has 62,000 miles. recently the check engine light went on and the scanner showed the codes P1128 (Bank 1), P1130 (Bank 2) and P0134 (Bank 1, sensor 1) this codes were obtained in Auotozone, shortly after that, the ABS light came on and the PCB lights, but this failure is intermittent.

The reality is that if it weren't for the light you wouldn't notice any fault, except for the absence of the ABS.

I took the car with Porsche’s dealer and they recommend changing the 4 oxygen sensors, during my visit I noticed that their records indicate they changed the oil separator about 6 months ago.

I decided to read a bit in this forum and I have doubts about the diagnosis. I opened the oil cap and the suction is minimal. I have the doubt if the problem is the oil separator even if the suction is not increased? I am concerned the O2 sensor aren’t the problem, Is it an open circuit suction problem or is it the MAF sensor?

I would appreciate any suggestion from the members of this forum since you have more experience, cordial greeting to the group.

The P0134 code is telling you that the DME/ECU is not getting any signal from the sensor.
So the sensor is dead or you have an issue with the wiring from the DME to the sensor.
Most likely a wiring issue.
I would look at the wiring connection at the sensor and the sensor wiring harness.

The other two codes are telling you that you have reached the rich mixture threshold.
So the DME/ECU is adding all the fuel it can. You most likely have Vacuum leak.

Thank you very much for your response, blue62.

I appreciate it, regards.

Any suggestions for the ABS light? Could it be the battery?
The dealers scanner couldn’t detect any code, the light was out at the moment.

Sorry no ideas on the ABS light.

I had ABS and PSM lights after about 15 to 30 minutes of driving and the cause was a faulty switch on the brake pedal. Does your Cruise Control work? Mine didn't until I replaced that switch.
Here's the replacement guide: https://www.pelicanparts.com/techarticles/Boxster_Tech/93-ELEC-Pedal_Switches/93-ELEC-Pedal_Switches.htm

For the other issue, I'm guessing MAF sensor is bad. If it hasn't ever been replaced, a new one wouldn't be a bad idea anyway. Go with a genuine Bosch, do not try a generic bargain.

thanks 78f350

If the ABS light is on the scanner could read a code or something?

A faulty switch in the brake pedal goes with a stop brake light malfunction?

Hi

"The P0134 code is telling you that the DME/ECU is not getting any signal from the sensor.
So the sensor is dead or you have an issue with the wiring from the DME to the sensor.
Most likely a wiring issue.
I would look at the wiring connection at the sensor and the sensor wiring harness."

I agree with the above except that I think it will be the o2 sensor. If it is the wiring I would be interested to know the fault. I have that code and for me it is an ECU problem. There again I did cut all the wires to the o2 sensor at once while the engine was running, so I have shorted something in the ECU out.

Best of luck

Berni

First lets look at what we are dealing with.
A code: P0134 when you look up that code it states: "pre cat O2 sensor cyl 1-3 signal implausible/open circuit/no signal.

There are three possibilities:
1. Bad ECU
2. Dead sensor
3. An issue with the wiring between the ECU and the sensor.
The car is a 2002 with 62000 miles.

An issue with the ECU is the least likely cause of the problem.
Unless of course the owner shorted it out while cutting some wires or doing other work while the engine was running. as you did in your case.
There could be an issue with the ECU but it doesn't happen often.

The second least likely issue is a dead O2 sensor. The car only has 62000 miles on it.
O2 sensor signals slowdown with age but very very rarely go compleately dead and give no signal.
There is also the matter of the P1128 code which is from the bank 1 pre cat O2 sensor.

This leaves the most likely cause of the P0134 code to be an issue in the wiring between the O2 sensor and the ECU.
Something as simple as a loose connection at the O2 sensor. Or the same at the ECU.
The signal wire could have rubbed and shorted. The ground wire could be loose or corroded.
The AOS was replaced in the past so maybe the O2 sensor wiring was disturbed in the process.
Always go with the simplest things first and work your way up the diagnostic tree step by step.;)

Some simple tests with a multimeter would tell you if it is the ECU, the sensor, or the wiring.

In my case it took months for me to figure it out because the brake light still worked. A scanner would have to be capable of reading the ABS module to get a code. Many of the inexpensive ones only read the engine module.

In addition to what Blue62 said about simple tests with a multimeter for the P0134, you can also try swapping the O2 sensors from one side to the other and see if the problem moves.

Are you familiar with the reference of 'bank 1, sensor 1'? That's the most forward O2 sensor on the right side.

I agree that you could test the O2 sensor by swapping it from one side to the other.
But that is a lot of work compared to testing it and associated wiring with a multimeter which only takes a few minutes. And no wrenching involved;)

Thank you very much for all your help!!

I am looking for MAF sensor and they ask me if my car has a M620 e-accelerator or not?
How can I determine it?

I appreciated all the assistance

All boxsters from 2000 forward have the M620 e-accelerator.
Have you tested the MAF sensor to see if it is faulty?

Assuming that Laredo has a multimeter and is familiar with the pin-out, yes. Even swapping the sensor requires possessing a proper wrench and that may not be the case, but is easier to figure out if unfamiliar.