Skip the auto shop - Our mechanics make house calls
  1. Home
  2. Articles
  3. P2189 OBD-II Trouble Code: Sys Too Lean at Idle Bank 2

P2189 OBD-II Trouble Code: Sys Too Lean at Idle Bank 2

Check Engine Light

P2189 trouble code definition

The most environmentally friendly and power efficient air-fuel ratio for gasoline engines that we modernly know is 14.7:1. The engine control module (ECM) is programmed to adjust things like fuel delivery and ignition timing if needed to keep the air-fuel ratio at or near the 14.7:1 ratio. Trouble code P2189 indicates that the ECM has determined that there is too much air and too little fuel present in the air-fuel ratio during engine idle.

What the P2189 code means

This code indicates that during the last two drive cycles, the ECM has observed a lean air-fuel ratio condition on bank 2 of the engine. The manufacture designed the ECM with the ability to adjust the air-fuel ratio by changing the ignition timing and fuel injection pulse width to help achieve 14.7:1. The ECM can only adjust the air-fuel ratio to a certain extent. If the margin of adjustment is too wide for the ECM to correct the lean condition, then a code P2189 will set.

What causes the P2189 code?

  • Faulty EVAP system purge valve
  • Vacuum leak
  • Faulty crankcase ventilation valve
  • Leaking crankcase ventilation valve grommet
  • Leaking intake manifold gaskets
  • Loose intake manifold
  • Faulty bank 2 oxygen sensor
  • Fuel pressure low due to weak fuel pump
  • Restricted fuel supply such as pinched fuel line or clogged fuel filter
  • Air intake leak
  • Loose oil cap
  • Faulty gas cap seal
  • Leaks in the exhaust system
  • Mechanical issue in one or more of the bank 2 fuel injectors
  • Faulty manifold absolute pressure sensor
  • Faulty fuel pressure regulator

What are the symptoms of the P2189 code?

  • Check Engine Light illumination
  • Misfire at idle
  • Engine hesitation
  • Engine hard to start, especially when warm
  • Whistling noises coming from the engine area

How does a mechanic diagnose the P2189 code?

  • Performing a fuel pressure test
  • Performing a fuel injector flow test
  • Inspecting the EVAP system for leaks
  • Inspecting the intake manifold for leaks
  • Inspecting the air intake and vacuum lines for leaks
  • Inspecting the crankcase ventilation grommet for leaks
  • Inspecting the rubber seal of the gas cap
  • Performing an inspection of the exhaust system
  • Using a scan tool to view the long and short-term fuel ratio
  • Using a scan tool to view the oxygen sensor live data

Common mistakes when diagnosing the P2189 code

Often times, a mechanic may not check the vacuum lines and EVAP system of the vehicle. The EVAP system and vacuum lines are among one of the most likely things to cause a lean condition.

How serious is the P2189 code?

It is fairly serious because an improper air-fuel ratio will generate excessive emissions, which will cause harm to the environment.

What repairs can fix the P2189 code?

Additional comments for consideration regarding the P2189 code

As there are many components which can cause this code, it is recommended to have an experienced technician point out the faulted component through proper testing and inspection to save time and money.

Need help with a P2187 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
How to Get a Louisiana Driver's Permit
s licensing program. The first step in this program is to obtain...
P2159 OBD-II Trouble Code: Vehicle Speed Sensor B Range/Performance
Diagnostic Trouble Code (DTC): P2159 P2159 code definition Vehicle Speed Sensor B Range/Performance...


Related questions

Q: P0700 Transmission Control System MIL Request

Hi! A P0700 code stored in the powertrain control module (PCM) indicates that there is a code stored in the transmission control module (TCM) that can be accessed by looking into the TCM with an appropriate scan tool. Having the...

Q: When I come to a stop my trunk starts shaking. Just started happening.

If the Check Engine Light has come on, it is likely that Diagnostic Trouble Codes have been stored and they can be retrieved by a scan tool. If there are downloadable codes, a Check Engine Light diagnostic will quickly reveal...

Q: Egr and evap codes 455 & 405

The trouble code P0405 is for the EGR sensor. This code indicates that the sensor is not giving correct voltage readings. You'll need to replace the sensor and the sensor hoses. The hoses can clog or burn through which causes...