P2188 OBD-II Trouble Code: System Too Lean at Idle Bank 1

Our certified mechanics come to you · Get a fair and transparent estimate upfront

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P2188 code

P2188 is a diagnostic trouble code (DTC) for "System Too Lean at Idle Bank 1". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$20.00
Toyota$20.00
BMW$20.00
SCHEDULE P2188 DIAGNOSTIC Get a fair and transparent estimate upfront

P2189 trouble code definition

The most environmentally friendly and power efficient air-fuel ratio is 14.7:1. The engine control module (ECM) is able to adjust the air-fuel ratio in limited increments if it defers from the 14.7:1 range. The P2188 “System Too Lean at Idle Bank 1” definition indicates that there is too much air and too little fuel in the air-fuel ratio detected by the ECM during engine idle.

What the P2188 code means

This particular trouble code means that a lean condition has been detected on bank 1 of the engine during idle. The ECM will attempt to correct the air-fuel ratio if the mixture becomes too lean.

The ECM will adjust fuel injector pulse width and ignition timing to alter the air-fuel ratio. If the lean condition is so excessive that the ECM can not bring the air-fuel ratio back to the desired range of 14.7:1, then a code P2188 sets.

What causes the P2188 code?

  • A worn or faulty gas cap seal
  • A leak in the exhaust system on the bank 1 side
  • Mechanical issue in one or more of the bank 1 fuel injectors
  • Faulty MAP (manifold absolute pressure) sensor
  • Flawed fuel pressure regulator
  • 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 1 oxygen sensor
  • Fuel pressure low due to weak fuel pump
  • A restricted fuel supply such as pinched fuel line or clogged fuel filter
  • Air intake leak
  • Loose oil cap

What are the symptoms of the P2188 code?

  • Engine hard to start, especially when hot
  • Whistling or hissing noises coming from the engine bay
  • Check Engine Light illumination
  • Misfire at idle
  • Engine hesitation

How does a mechanic diagnose the P2188 code?

  • 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
  • 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

Common mistakes when diagnosing the P2188 code

Commonly, a worn vacuum line or EVAP leak will cause this code. However, multiple mechanics have overlooked this simple fix. It is important to thoroughly inspect the vacuum lines and the EVAP system if this trouble code is encountered.

What repairs can fix the P2188 code?

Additional comments for consideration regarding the P2188 code

As there are many components which could cause the exact same code, if a failure is recognized, it is recommended to have an experienced technician highlight the faulted component(s) through proper testing and inspection to save both time and money.

Need help with a P2188 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.

trouble codes
P2188
Check Engine Light

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P2188 code.

SCHEDULE P2188 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.8/5

Number of Reviews

5,395

Rating Summary
4,978
202
50
30
135
4,978
202
50
30
135

Anthony

6 years of experience
18 reviews
Anthony
6 years of experience
Jeep Grand Cherokee - Check Engine Light is on - Carmichael, California
Anthony was great! We are very happy that we chose to go with this company instead of the overpriced and slow service we get from the Jeep dealership. He was on time and did the job just as expected. He identified a couple of other things that need to be done before the problems get worse. We appreciate having a technician give us direct feedback regarding our vehicle, rather than a service advisor (salesperson) that we've had to deal with in the past at the dealership. We'll be booking the addtional services very soon and will definitely request Anthony again now that he is familiar with our vehicle!

Michael

37 years of experience
113 reviews
Michael
37 years of experience
Subaru Forester - Check Engine Light is on - Santa Fe Springs, California
Michael was punctual and courteous. He knows what he’s doing and I would absolutely recommend him to anyone.

Anthony

6 years of experience
18 reviews
Anthony
6 years of experience
BMW 740Li - Check Engine Light is on - Roseville, California
Very helpful in finding out the fault codes in my bmw 740 li. It was simple fix and that the two tube hose just had to be connected and my drive train malfunction went away. This saved me from having to go the an expensive dealership. Anthony has a good attitude about his work.

Breck

19 years of experience
613 reviews
Breck
19 years of experience
Ram 1500 - Check Engine Light is on - Houston, Texas
Breck did a great job working on my truck. Showed up on time, found any issues I had on my truck and explained everything to me so that I understood what was going on. Went above and beyond, definitely will book him for future appointments.


More related articles

P0083 OBD-II Trouble Code: Intake Valve Control Solenoid Circuit High (Bank 2)
P0083 P0083 code definition P0083 is a general OBD-II code indicating a issue with bank 2 intake valve control solenoid. This code may be seen with P0081 and P0082. The vehicle also has a bank 1 valve control solenoid. What...
P2259 OBD-II Trouble Code: Secondary Air Injection System Control B Circuit Low
P2259 P2259 code definition Secondary Air Injection System Control B Circuit Low What the P2259 code means P2259 is an OBD-II generic code. The engine control module (ECM) monitors the secondary air injection system control valve circuit when the system...
P0801 OBD-II Trouble Code: Reverse Inhibit Control Circuit Malfunction
P0801 means an issue with the reverse inhibitor switch making the vehicle unable to be placed in reverse or capable of doing so while driving forward.

Related questions

Loss of engine power when driving over 50 mph

Check for problem codes, even if the Check Engine Light is not illuminated right now. There are likely transient codes still set. This may be something simple like a fuel supply issue (fuel filter clogged, fuel pump relay contacts burned,...

Check engine light and the engine is making a humming noise.

The humming noise could be the air filter being dirty, the drive belt slipping, or the air conditioning clutch is slipping. It is safe to drive your vehicle to the appointment as long as there is no smells or loud...

Check Engine light back on

The two code are for two different issues and if both codes were not fixed, or after the repairs the engine self learn was not reset, then the light may come back on and the car not run correctly. I...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com