Too rich and too lean! Ahhhhh

[bowen]

Hi guys,

Recently had some running problems with my a4 b6 cab, BFB engine code. I was getting 3 codes; running rich,running lean and high rpm at idle. With a bit of research it led me to the crankcase breather valve. I replaced this and a good job I did as the old one was shafted. Now I have replace it with a genuine part I have just got CEL 17545 and 17536 running rich and lean?! How!? It had a new maf around a month ago.

Any help would be great, thanks.

 

[marktdisport]

would a lambda sensor cause your faults bowen ... just a guess !!!!

 

[bowen]

I've looked at Ross tech, it does suggest lambda sensor, maf or vac/boost leak? Im getting it smoke tested next week, that should eliminate the leak, hopefully.

 

[quattro tony]

I would be looking at all the rubber hoses around the throttle valve carefully for any splits, deterioration, holes etc..... Especially between the air mass meter and the throttle valve. An air leak could cause a high idle and mixture trim faults.

 

[bowen]

i hope the smoke test shows up an air leak!

will let you know.

 

[bowen]

Does any one have an etka for the diverter valve location?

 

[olly quattro]

diverter valve is down the bottom of the engine bay accessed from under the car, Number 14

 

[bowen]

found it, cheers mate!

 

[bowen]

Ok, so i had no leaks from the smoke test. I still get 17545 and 17536.

Also to note, my temp gauge works intermittently? would this cause these codes, it has had a new temp sensor last mont though?

 

[quattrojames]

What *exactly* does the Ross-Tech wiki list those codes as?

 

[bowen]

[h=2]17545/P1137/004407 - Fuel Trim: Bank 1 (Add): System too Rich[/h][h=4]Possible Symptoms[/h]

• Malfunction Indicator Light (MIL) active

[h=4]Possible Causes[/h]

• Mass Air Flow (MAF) Sensor faulty
• Fuel Pressure Regulator faulty
• Fuel Injector(s) faulty
• Oxygen Sensor Control faulty
  • Oxygen Sensor(s) faulty
• Evaporative Emission (EVAP) System faulty

[h=4]Possible Solutions[/h]

• Check Mass Air Flow (MAF) Sensor
• Check Fuel Pressure Regulator
• Check Fuel Injector(s)
• Check Oxygen Sensor Control
  • Check Oxygen Sensor(s)
• Check Evaporative Emission (EVAP) System

 

[bowen]

[h=2]17536/P1128/004392 - Fuel Trim; Bank 1 (Mult): System too Lean[/h][h=4]Possible Symptoms[/h]

• Malfunction Indicator Light (MIL) active

[h=4]Possible Causes[/h]

• Mass Air Flow (MAF) Sensor faulty
• Oxygen Sensor Control faulty
  • Oxygen Sensor(s) faulty
• Fuel Injector(s) faulty

[h=4]Possible Solutions[/h]

• Check Mass Air Flow (MAF) Sensor
• Check Oxygen Sensor Control
  • Check Oxygen Sensor(s)
• Check Fuel Injector(s)

 

[bowen]

My next point of call is Lambda sensor/s

 

[InFlames]

Hi! I have almost the same problem
My car is a A4 2.0 liter engine, ALT sedan 2001
There is two recurring error in Engine. I also linked what suggest ross-tech wiki

16804/P0420/001056 - Catalyst System; Bank 1: Efficiency Below Threshold

Possible Causes

• Leakage in Intake and/or Exhaust System
• Catalyst faulty
• Oxygen Sensor(s) faulty
• Oxygen Sensor(s) Control faulty

Possible Solutions

• Check Intake and Exhaust System for Leaks
• Check Catalyst
• Check Oxygen Sensor(s)
• Check Oxygen Sensor(s) Control
  • Perform Oxygen Sensor(s) Aging Check

17544/P1136/004406 - Fuel Trim: Bank 1 (Add): System too Lean

Possible Solutions

• Check Mass Air Flow (MAF) Sensor
• Check Fuel Pressure Regulator
• Check Fuel Pump
• Check Intake/Exhaust System for Leaks
• Check Secondary Air Injection for Leaks
• Check Vacuum Lines for Leaks

I have checked both O2 (lambda) sensor's heater resistance.
View attachment 10383View attachment 10384


G130 (4 pin connector) lambda probe's resistance between 2 and 1 pin was 8 Ohm around ~ 5°C I think this is OK
G39 (6 pin connector) lambda probe's resistance between 4 and 3 pin was 2,7 Ohm around ~ 5°C Is this resitance OK?
G39 had a cap, I took off and take measured. I find it is the 6 and 2 pin was 107,9 Ohm around ~ 5°C

View attachment 10387

Measuring Block 006 field 4 Lambda was -3,1%

Last week was -4,7%

View attachment 10386

I also find a manual. O2_Sensor_Testng_DIY V2.pdf
View attachment 10380

In field 2 I had a readout of ~1,5 V, wich is out of spec 0 V - 1 V. What is wrong?
View attachment 10381
View attachment 10382

That's it until now.
Any thoughts?