P0421 Diagnostic Trouble Code Discussion for June 2008
Warmup Catalyst Efficiency Low (Bank 1)
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| Help Request | Posted | |
| 2002 Kia Optima SE 2.4L Stall, MIL Lamp on, lacks power VIN: KNAGD12682 P0421: Catalyst Efficiency Below Normal (Bank 1). the car runs fine at idle, but under load when driving has low power and will not accelerate over 40 MPH without stalling. The computer codes lead us toward the catalytic converter, however a vacuum test to check for exhaust restriction indicates no restrictio... |
June 19, 2008 |
