Lotus Service Notes Section EMR
Page 67
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:
• Batteryvoltagebetween10–16V
• Coolanttemperaturebetween-10–120°C(14–248°F)
• Enginespeedbetween480–8010rpm
• Enginespeedtransient>15rpm
• Altitude<8000ft(2438m)/Baro>756mbar
• Fuellevel>5litres(1.3USgallons)
• Engineloadgreaterthan14–25%dependingonenginespeed
Disable Criteria:
• DFCOenabled(DecelerationFuelCutOff)
• Roughroad
• MAFfaults
Malfunction Criteria:
• P1301EmissionsFailure–Misfirepercentage>7%measuredover1000enginerevolutions.
• P1302CatalystDamageFailure–Misfirepercentage>16.6%-40%dependingonenginespeedandload,
measured over 200 engine revolutions.
Potential failure modes:
• Injectorrelatedcodes,asthesecancausemisfirecodestobeset.
• VVTcodesset
• Sensorconnectorandwiringforsignsofcorrosionorlooseconnections
• Sparkplug/cylindercompression
• Camtiming/damagetorockerarmassembly
• Fuelpressure
Diagnostic Masks:
• ForaP1301faultcodetheMILwillbeilluminatedimmediately.
• ForaP1302faultcodetheMILwillbeilluminated immediatelyandtheECMwilltakeactiontoprevent
catalyst damage.
Notes:
• MisfirelearnsarecalculatedduringDFCO(DecelerationFuelCutOff)
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