# 16795 16685 16684 17658 Fault Codes



## zwiefe (Nov 4, 2008)

16795 16685 16684 17658 Fault Codes

This is the second time that this has happened to me. My car would run like complete crap, and what it feels like, is the engine misfiring, or not getting any fuel. Any help?
I have a cheap obd scanner and these are the codes that came up. Also ever time that I accelerate the CEL flashes and the car starts jumping around.

*16795: Secondary Air Injection System: Incorrect Flow Detected*
Possible Symptoms

* Malfunction Indicator Light (MIL) ON 

Possible Causes

* Fuel Pump Relay (J17) faulty
* Hoses/Pipes to/between Components faulty/clogged
* Secondary Air Injection Pump (V101) faulty
* Secondary Air Injection Pump Relay (J299) faulty
* Secondary Air Injection Solenoid Valve (N112) faulty 

Possible Solutions

* Check Fuel Pump Relay (J17)
* Check Hoses/Pipes to/between Components
o Check Secondary Air Injection Hoses/Pipes for Carbonization 
* Check Secondary Air Injection Pump (V101)
* Check Secondary Air Injection Pump Relay (J299)
* Check Secondary Air Injection Solenoid Valve (N112) 

*16685: Cylinder 1 Misfire Detected*
Possible Causes

* Ignition system
* Fuel injectors
* Fuel pressure
* Running out of fuel
* EVAP canister purge valve
* Evaporative emission system
* Low compression
* Base engine problems
* Controle Module damaged 

Special Notes: This feature search for engine misfire in a specific cylinder. Most of the time the cause for a misfire is a lack of combustion in a cylinder due to absence of spark, poor fuel metering, or poor compression.

*16684: Random/Multiple Cylinder Misfire Detected*

Possible Causes

* Air Intake System leaking
* Fuel Supply faulty
* Injector(s) faulty
* Ignition Cable(s) and/or Spark Plug(s) faulty
* Ignition Coil(s) faulty
* Exhaust Gas Recirculation (EGR) Valve (N18) stuck/open
* Camshaft Position Sensor (G40) faulty 

Possible Solutions

* Check Misfire Recognition
* Check Air Intake System
* Check Fuel Supply
* Check Injector(s) and Injector Sealing
* Check Ignition Cable(s) and Spark Plug(s)
* Check Ignition Coil(s)
* Check Exhaust Gas Recirculation (EGR) Valve (N18)
* Check Camshaft Position Sensor (G40) 

*17658: Fuel level to low*

I do not know why the last one came up. This has only happened when I have plenty of gas.

Helps if I post the car. 1998 Audi A4 2.8L 30V Wagon Not quattro, 178,000miles,


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## ps2375 (Aug 13, 2003)

Some things to do/look at:

16795: Secondary Air Injection System: Incorrect Flow Detected

Replace ALL vacuum lines on motor. The combi valves are vacuum operated via a solenoid valve and are known to crack and leak.

16685: Cylinder 1 Misfire Detected

How old are plugs and wires? General maintenance is very important.


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