Lotus Evora. Manual - part 26

 

 

Lotus Service Notes   

 

 

  Section EMR

Fuel Control System Too Lean Or Rich

P0171  System Too Lean (Bank 1)

P0172  System Too Rich (Bank 1)

P0174  System Too Lean (Bank 2)

P0175  System Too Rich (Bank 2)

Description

The oxygen sensor sends a signal to the ECU corresponding to the exhaust gas oxygen content enabling the 

ECU to maintain a 14.7:1 air/fuel ratio under normal driving conditions. The ECU can make fuel corrections of 

± 30% to the calculated fuel demand. This value is then learned by the ECU over time. If the ECU determines 

a rich condition exists (oxygen sensor above 450mV), it will decrease the calculated fuel demand to maintain 

a 14.7:1 ratio. If the ECU determines a lean condition exists (oxygen sensor below 450mV), it will increase the 

calculated fuel demand to maintain a 14.7:1 ratio.

Monitor: 

•  Continuous

Enable Criteria:

•  Fuel Trim condition enabled

•  Closed loop fuelling enabled

•  MAF < 28 g/sec

•  Altitude < 8000 ft (2438 m), Baro > 756 mbar

Disable Criteria P0171 & P0172:

•  P0106, P0107, P0108                – Baro sensor faults

•  P0131, P0135                      – Oxygen sensor faults

•  P0300, P0301, P0302, P0303            – Misfire faults

•  P0111, P0112, P0113                  – Intake air temperature faults

Disable Criteria P0174 & P0175:

•  P0106, P0107, P0108                – Baro sensor faults

•  P0151, P0155                      – Oxygen sensor faults

•  P0300, P0304, P0305, P0306            – Misfire faults

•  P0111, P0112, P0113                  – Intake air temperature faults

Malfunction Criteria P0171 & P0174: 

•  These codes will set when the relevant engine bank learned fuel correction has been increased to its maximum

limit of 25% and the system still cannot maintain an air/fuel ratio of 14.7:1 under normal driving conditions.  

•  These codes will also be set if the relevant bank fuel learn injector dead time is greater than 450 micro

seconds.

Potential failure modes:

•  Fuel Pressure too low (restriction in fuel line)

•  Air leak in induction system

•  Water in fuel

•  Exhaust leak / crack before front oxygen sensor

•  Injector fault

•  Sensor connector and wiring for signs of corrosion or loose connections

•  MAF fault

•  Vehicle has previously run out of fuel

Diagnostic Mask:

•  The MIL will be illuminated if fault is present for two consecutive trips.

2009/02

 

 

Lotus Service Notes   

 

 

  Section EMR

Malfunction Criteria P0172, P0175: 

•  These codes will be set when the relevant bank learned fuel correction has been decreased to its minimum

limit of -25% and the system still cannot maintain an air/fuel ratio of 14.7:1 under normal driving conditions.  

•  These codes will also be set if the relevant bank fuel learn injector dead time is less than -450 micro sec-

onds.

Potential failure modes:

•  Fuel pressure too high

•  Leaking fuel injector

•  Restriction in the exhaust system or air intake / filter

•  Erratic throttle position sensor

•  MAF fault

•  O2 sensor fault

•  Ignition fault

Diagnostic Mask:

•  The MIL will be illuminated if a fault is present for two consecutive trips.

 

2009/02

 

 

Lotus Service Notes   

 

 

  Section EMR

Fuel Injection System

P0261  Injector Circuit low voltage – Cylinder 1

P0262  Injector Circuit high voltage – Cylinder 1

P0264  Injector Circuit low voltage – Cylinder 2

P0265  Injector Circuit high voltage – Cylinder 2

P0267     Injector Circuit low voltage – Cylinder 3

P0268     Injector Circuit high voltage – Cylinder 3

P0270  Injector Circuit low voltage – Cylinder 4

P0271  Injector Circuit high voltage – Cylinder 4

P0273  Injector Circuit low voltage – Cylinder 5

P0274  Injector Circuit high voltage – Cylinder 5

P0276  Injector Circuit low voltage – Cylinder 6

P0277  Injector Circuit high voltage – Cylinder 6

Description

The ECU has six injector driver circuits, each of which controls an injector. When the engine is running the 

ECU continuously monitors the injector circuit feedback signals. The monitored feedback signal should be low 

voltage when the injector is ON and high voltage when the injector is OFF.

Component connections

Injector    ECU Pin    ECU Connector

1            H4          32 Way (Left)

2            H3          32 Way (Left)       

3            H2           32 Way (Left)

4            H1       32 Way (Left)

5                      G4             32 Way (Left)

6                      G3             32 Way (Left)

Monitor: 

•  Continuous

Enable Criteria: 

•  Engine running

Potential failure modes:

•  Sensor connector or wiring corroded or loose connections

Diagnostic Mask:

•  The MIL will be illuminated if these faults are present for 2 consecutive trips.

Limp home:

•  Limit maximum engine speed to 4000rpm

•  Return the fuel system of the affected bank to open loop fuel control

Notes:

If an injector goes short circuit it is likely that the ECU injector driver will be damaged.

 

2009/02

 

 

Lotus Service Notes   

 

 

  Section EMR

Misfire

P0300  Random/Multiple Cylinder Misfire Detected

P0301  Cylinder 1 Misfire Detected

P0302  Cylinder 2 Misfire Detected

P0303  Cylinder 3 Misfire Detected

P0304  Cylinder 4 Misfire Detected

P0305  Cylinder 5 Misfire Detected

P0306  Cylinder 6 Misfire Detected

Description

A misfiring cylinder can be detected by analysing crank speed variation. As a result of a combustion event there 

will be a net acceleration of the crankshaft. Subsequent to a misfire event the engine will decelerate over the 

period following the missed cylinder event.   

Speed changes can be characterised by observing changes in the time period for a fixed angle of rotation after 

firing events. A significant change in this period, assessed by comparison to previous periods, may be attributed 

to misfire on a known cylinder. 

Component connections                   

Connector  Description          ECU Pin                            ECU Connector

1        Supply Voltage        Coil 1    Coil 2    Coil 3    Coil 4    Coil 5    Coil 6

2        Ignition Coil Feedback     D2        D2      D2         D2       D2     D2        32 Way (Left)

3        Coil Output (Logic)       F4        F3      F2         F1       E4        E3        32 Way (Left)

4        Ground                     

Malfunction Criteria

The operation of all the misfire codes is the same, the last digit relates to the misfire involved i.e. a code P0303 

indicates there is a problem with cylinder number 3. 

P0300 indicates the misfire is random and not linked to one particular cylinder.

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:

•  Individual cylinder misfire in excess of 10% of total engine misfire

•  P300 set when more than one cylinder misfiring or when CAM error MIL requested

Limp home (depends on severity and number of cylinders affected):

•  Throttle limited and engine continues to run on all cylinders

•  Fuel system set to open loop control

•  Affected bank shut down and engine speed limited to 4000 rpm

2009/02