Renault Megane 2 1.4 16v 2003 - High Idle, no fault codes, charging duty cycle - Fixed #
Posted by Terry Wood on March 2, 2010, 1:06 pm
Year of Manufacture *: 2003 Engine Code or CC *: 1.4 16v ( Optional ) Scanner Used: Autodiagnos
Hello all Have the above vehicle with high Engine idle approx 3000rpm No faults codes stored Done all the usual checks e.g. Plugs, air leaks, clean throttle housing, valve timing with no improvement.
Car has been to main dealer and have said the alternator duty cycle is constantly at 99.2% causing engine ECU to raise revs to compensate
Have the vehicle back but unfortunately Autodiagnos doesn't list Alternator duty cycle just ECU Voltage at 14.3v
Have tried swapping battery with no difference
if you remove the 2 pin multi plug on the alternator the Normal Idle speed is resumed
Have checked for feeds to 2 pin connector unplugged with Ign on engine off both pins had 12v
When plugged in PIN 1 (1.2 volts) PIN 2 (0 volts)
Engine Running PIN 1 (14.3 volts) PIN 2 (0 volts)
Question is what should this be? Is this model known for alternator faults causing this?
Have included the live data 1st is Connector plugged in 2nd is Unplugged running idle closed loop
Thanks Terry
Engine: Monitor list (56 values saved)
Description Value Computer Supply Voltage 14.37V Computer + After Ignition Present Water Pump Command Inactive Vehicle Speed 0km/h Brake Pedal Inactive Clutch Pedal Inactive Water Temperature 83°C Actuator Relay Control Active Starting Prohibited Code Programmed Yes Engine Immobliser Inactive Air Conditioning Presence No Compressor Operation Requ Inactive Air Con Authorisation No Refrigerant Pressure 0.0bar Engine Speed 1841rpm Accelerated Idle Request Absent Power Absorbed By The AC Compressor 11.8W Fan Control 1 Not Done Fan Control 2 Off Number of Passenger Compartment No Heating Resistors Fixed (Set By A/C) Rch Cut Out No Atmospheric Pressure 1025mbar Inlet Pressure 407mbar Boost Pressure 103mbar Turbo Solenoid Valve OCR Setting 1% Air Tempurature 29°C Camshaft Phase Shifter In Defect Mode No Camshaft Offset Status1 Camshaft Offset Control Inactive Camshaft Dephaser Measured Position 0d° Camshaft Dephase OCR Sett 0% Idle Speed Correction 0rpm Idle Control Inactive Idle Regulation Reference 752rpm Idle Regulation Programming Value 42090675.2% Idle Regulation Integral Correction 53.8% Theoretical Idle Regulation RCO 45.6% Richness Loop Through Upstream Sensor Open Richness Correction 51.7% Richness Auto Adaptive Offset 128 Richness Auto Adaptive Gain 128 Injection Duration 3.61ms Instantaneous Fuel Consumption 0.1l/h Fuel Pump Command Circuit Active LPG Faulty No LPG Ready No LPG Tank Empty No Operating In LPG Mode No Operating In Petrol Mode Yes Transition From Petrol Mode To LPG Not Done Transition From LPG Mode To Petrol Not Done LPG Mode Switching Conditions Incorrect Motorised Throttle In Downgraded Mode No Programming Throttle Limits Done Motorised Throttle Position Closed
Engine: Monitor list (56 values saved)
Description Value Computer Supply Voltage 14.34V Computer + After Ignition Present Water Pump Command Inactive Vehicle Speed 0km/h Brake Pedal Inactive Clutch Pedal Inactive Water Temperature 86°C Actuator Relay Control Active Starting Prohibited Code Programmed Yes Engine Immobliser Inactive Air Conditioning Presence No Compressor Operation Requ Inactive Air Con Authorisation No Refrigerant Pressure 0.0bar Engine Speed 730rpm Accelerated Idle Request Absent Power Absorbed By The AC Compressor 11.8W Fan Control 1 Not Done Fan Control 2 Off Number of Passenger Compartment No Heating Resistors Fixed (Set By A/C) Rch Cut Out No Atmospheric Pressure 1025mbar Inlet Pressure 407mbar Boost Pressure 103mbar Turbo Solenoid Valve OCR Setting 1% Air Tempurature 30°C Camshaft Phase Shifter In Defect Mode No Camshaft Offset Status1 Camshaft Offset Control Inactive Camshaft Dephaser Measured Position 0d° Camshaft Dephase OCR Sett 0% Idle Speed Correction 0rpm Idle Control Active Idle Regulation Reference 752rpm Idle Regulation Programming Value 42090675.2% Idle Regulation Integral Correction 38.4% Theoretical Idle Regulation RCO 6.4% Richness Loop Through Upstream Sensor Open Richness Correction 30.0% Richness Auto Adaptive Offset 128 Richness Auto Adaptive Gain 128 Injection Duration 3.17ms Instantaneous Fuel Consumption 0.0l/h Fuel Pump Command Circuit Active LPG Faulty No LPG Ready No LPG Tank Empty No Operating In LPG Mode No Operating In Petrol Mode Yes Transition From Petrol Mode To LPG Not Done Transition From LPG Mode To Petrol Not Done LPG Mode Switching Conditions Incorrect Motorised Throttle In Downgraded Mode No Programming Throttle Limits Done Motorised Throttle Position Closed
Re: Renault Megane 2 1.4 16v 2003 - High Idle, no fault codes, charging duty cycle #
As Mick said the alt can cause this. The second pin carries the load info and should be approx 50% duty cycle at idle (depends on a list of things) and 100% at full load (electrical load). Yours is reading 100% at 0 volts and so the engine ECU has 'lifted' the revs to compensate.
Make sure you use a proper smart charge unit if you do fit one.
Hth Sean
Ps I think you could plug the replacement in prior to fitting and check for a duty cycle(earth the unit).
Re: Renault Megane 2 1.4 16v 2003 - High Idle, no fault codes, charging duty cycle #
New alternator arrived today supplied by car dealer who's car it was unfortunately i just fitted it unlike what Sean suggested by just plugging it in.
then to find it was not a smart charge alternator which gave a fault code of
2502 Charging System Voltage 4E
after calls to the supplier who was a little unsure as the part number of old unit crossed over
I was then given a Hella unit which went straight on with no problems
The only thing i noticed between the non smart charge and the Smart charge versions was the letters DF molded into the plastic casing next to the 2 pin connector and also on the label
The non smart charge alternator was only marked with a L
Below is a good Duty signal of white wire on pin 2 at the alternator
on March 2, 2010, 6:06 pm, in reply to "
