adrian.denizs4

Recently the check engine light came on in my 2001 S4. I pulled the codes and found the following 8;
8 Faults Found:
17865 - Exhaust Gas Temp Sensor 2 (G236): Open or Short to Plus
******* P1457 - 35-10 - - - Intermittent
17861 - Shareware Version. To Decode all DTCs
******* P1453 - 35-10 - Please Register/Activate - Intermittent
17965 - Shareware Version. To Decode all DTCs
******* P1557 - 35-00 - Please Register/Activate
17521 - Oxygen (Lambda) Sensor: B1 S1: Internal Resistance too High
******* P1113 - 35-10 - - - Intermittent
17535 - Shareware Version. To Decode all DTCs
******* P1127 - 35-00 - Please Register/Activate
17537 - Shareware Version. To Decode all DTCs
******* P1129 - 35-00 - Please Register/Activate
17831 - Secondary Air Injection System: Bank 1: Insufficient Flow
******* P1423 - 35-00 - -
17819 - Shareware Version. To Decode all DTCs
******* P1411 - 35-00 - Please Register/Activate

I was told it needs a new secondary air pump and relay to solve the issue, which is now in the mail for a few ducets. Yet this is to pre heat the cats at cold start. Another issue im having with the car is while driving the rpm's seem to jump around between 1-2K, and poor boost response when on the throttle. Is this due to the O2 sensor failing ? Any insight would be great, losing my mind trying to fix this car.

complacentsee

A heads up for the future, http://www.s4biturbo.com/dtc_search.cgi

I'll post back once I'm finished searching them all.

complacentsee

17865 - Exhaust Gas Temp Sensor 2 (G236): Open or Short to Plus
******* P1457 - 35-10 - - - Intermittent

This code is pretty self explanitory, you need to replace your EGT sensor on bank 2.
(could possibily be a wiring harness issue)

17861 - Shareware Version. To Decode all DTCs
******* P1453 - 35-10 - Please Register/Activate - Intermittent

DTC: 17861
P-Code: P1453
Description: Exhaust gas temperature sensor 1 open/short to B+

Same as above, but with bank 1 sensor.

Those sensors are pretty expensive, are when the fail cause issues with misfiring, boost, running rich.


17965 - Shareware Version. To Decode all DTCs
******* P1557 - 35-00 - Please Register/Activate

DTC: 17965
P-Code: P1557
Description: Charge Pressure Contr. Positive Deviation

This means that you are overboosting, surging, and the the ECU will throw the car into limp mode, cutting down your boost. Commin cause of this would be a failure in the N75 valve, or a torn waste gate line. You can test the waste gate lines, there is probabaly a guide if you do some searching.

17521 - Oxygen (Lambda) Sensor: B1 S1: Internal Resistance too High
******* P1113 - 35-10 - - - Intermittent

I would hold off on this one, until the EGTs were replaced. However most likly your Primary (S1) Bank 1 (B1) oxygen sensor is aging and failing. This will effect the fuel going to the engine which will cause alot of performance issues.

17535 - Shareware Version. To Decode all DTCs
******* P1127 - 35-00 - Please Register/Activate

Long Term Fuel Trim mult.,Bank1 System too Rich

This can definatly be one is usually caused by a boost leak, bad 02 sensor, or failing EGT.

17537 - Shareware Version. To Decode all DTCs
******* P1129 - 35-00 - Please Register/Activate

17537 - Fuel Trim; Bank 2 (Mult): System too Rich
P1129 - 35-00 - -

Same as above.

17831 - Secondary Air Injection System: Bank 1: Insufficient Flow
******* P1423 - 35-00 - -
17819 - Shareware Version. To Decode all DTCs
******* P1411 - 35-00 - Please Register/Activate


Both those are:

Secondary Air Injection System: Bank 1: Insufficient Flow
Secondary Air Injection System: Bank 2: Insufficient Flow

Most likly the SAI pump as you mentioned already purchasing.



First off, I would clear the codes and pressure test for boost leaks. Including pressure testing the wastegate lines. Then I would fix any boost leaks I found and replacing the waste gate lines if nessisary. Then I would drive around for a while and see which codes came back. Most likey, your EGT and 02 sensor ones will remain as well as your SAI system codes. If the EGT codes remain, repalce the EGT sensors when the fail, they cause some major headaches and wierd issues. If the O2 sensor codes come back, fix whichever O2 sensor the code is for. (If they are secondary O2 sensors (B1S2 or B2S2) I would personally forget about them unless you need to pass emissions or really want the check engine light to go out) Finally, if you still have positive deviation code, I would probabaly replace the N75 valve.

adrian.denizs4

Thanks for your time and effort for the response. Extremely helpful, hopefully narrowing down the issues this weekend. I was looking to replace the relay for the SAI system, as I was told the leading cause of the pump failure was water entering the relay. I looked online and couldnt find much on the relay, was wondering if you knew where it was located or any insight on that dilemma? As for the charge fault code, do you think it is because its running so rich and the sensors are failing? I may have to take it into the shop to deal with the pressure issue, I dont have any of the tools to do this. But looking to take care of the airpump, just cant find this relay.

Thanks again