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Diagnostic Trouble Code
P2187

System Too Lean at Idle (Bank 1) DTC

Technical Description P2187

System Too Lean at Idle (Bank 1)

What Does This Mean P2187?

This diagnostic trouble code (DTC) is a generic powertrain code. It is considered generic because it applies to all makes and models of vehicles (1996-newer), although specific repair steps may be slightly different depending on the model. We have seen this code on Hyundai, Dodge, and other models.

This is an ambiguous code in of itself. It can be a tough code to crack without a diagnostic strategy. During the last two starts, the engine management computer has recognized a problem with the fuel mixture at an idle.

It appears that the fuel mixture is too lean (too much air and not enough fuel) at an idle. If you have a 4 cylinder engine the "Bank 1" is meaningless, however, if you have a 6 or 8 cylinder engine, Bank 1 will be on the side with the number one cylinder. Code P2189 is the same code but for Bank #2.

There is a laundry list of components that could cause this scenario. For the most part the diagnostic procedure is not difficult -- just time consuming, unless it is one of the first items checked. The strategy dictates that the driveability problems are observed and noted, then start with the most commonly found problems and progress from there.

Symptoms P2187

1 Vehicle has a miss at an idle
2 Hard to start, especially when hot
3 Very irregular idle
4 Additional codes to pinpoint cause of original P2187 code
5 Whistling noises
6 Lower turbo boost numbers
7 Fuel smell

Possible Causes P2187

1 Faulty O2 sensor (front)
2 Faulty gas cap seal
3 Leaky or loose oil filler cap
4 Air leaking into the intake manifold downstream from the Mass Airflow sensor due to the manifold itself, vacuum hoses off or cracked, leak MAP sensor, Leak at turbo bypass or it's stuck open, power brake booster hose, or a leak in the EVAP system hoses.
5 Faulty MAP sensor
6 EVAP canister purge valve
7 Fuel injector leak
8 Fuel pressure regulator faulty
9 Leaks in the exhaust system
10 Faulty variable camshaft timing
11 Faulty ECM (engine management computer)
12 Faulty O2 preheater (front)
13 Clogged fuel filter
14 Fuel pump wearing out and producing low pressure.
15 Faulty mass air flow sensor