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Lotus Service Notes
Section EMR Misfire P1301 Misfire level causing emissions increase P1302 Misfire level causing catalyst system damage Description When the engine misfire reaches a high enough percentage the engine emission output levels can exceed the allowed limits, this will produce the fault code P1301. If the misfire percentage is high enough and there is a possibility that the catalyst may be damaged then code P1302 will be set. To prevent catalyst damage the ECM may take action to either shut down the engine bank containing the misfiring cylinder and limit the engine speed to 4000rpm, or limit the throttle opening if there is more than one cylinder misfiring. See misfire faults P0300, P0301, P0302, P0303, P0304, P0305, P0306 Monitor: • Continuous Enable Criteria: • Battery voltage between 10 – 16 V • Coolant temperature between -10 – 120°C (14 – 248°F) • Engine speed between 480 – 8010rpm • Engine speed transient > 15rpm • Altitude < 8000 ft (2438 m) / Baro > 756mbar • Fuel level > 5 litres (1.3 US gallons) • Engine load greater than 14 – 25% depending on engine speed Disable Criteria: • DFCO enabled (Deceleration Fuel Cut Off) • Rough road • MAF faults Malfunction Criteria: • P1301 Emissions Failure – Misfire percentage > 7% measured over 1000 engine revolutions. • P1302 Catalyst Damage Failure – Misfire percentage > 16.6% - 40% depending on engine speed and load, measured over 200 engine revolutions. Potential failure modes: • Injector related codes, as these can cause misfire codes to be set. • VVT codes set • Sensor connector and wiring for signs of corrosion or loose connections • Spark plug / cylinder compression • Cam timing / damage to rocker arm assembly • Fuel pressure Diagnostic Masks: • For a P1301 fault code the MIL will be illuminated immediately. • For a P1302 fault code the MIL will be illuminated immediately and the ECM will take action to prevent catalyst damage. Notes: • Misfire learns are calculated during DFCO (Deceleration Fuel Cut Off)
2009/02 |