Help needed with fault code.

[John C]

Hi

Just wondered if any one can help me.
I have just bought a 2005 Lotus Elise and it had the following fault codes when I got the car.PO139 and P0448.
I have replaced the Vacuum switch control valve and this has left me with the one code remaining P0448.
Have any of the members had this problem and if so could you point me in the right direction to solving it.

Any help would be greatly appreciated.

[skelliott2]

This post gives a listing of many of the codes including the one you mentioned:

CEL Codes

Hope it helps.

[TimMullen]

First you need to download a copy of the Factory Service Manual from LCU -
it costs $25 - there is a sticky thread in the maintenance section of the forum explaining how to get the download.


From the Service Manual:
[b]Evaporative Emission Control – Purge, Open / Closed Circuit

P0444 Evaporative Emission System Purge Control Valve Circuit Open
P0445 Evaporative Emission System Purge Control Valve Circuit Closed
P0446 Evaporative Emission System Vent Control Circuit
P0447 Evaporative Emission System Vent Control Circuit Open
P0448 Evaporative Emission System Vent Control Circuit Closed
P0451 Evaporative Emission System Pressure Sensor/Switch Range/Performance
P0452 Evaporative Emission System Pressure Sensor/Switch Low
P0453 Evaporative Emission System Pressure Sensor/Switch High

Description
When the engine is running the ECU continuously monitors the feedback signals from the evaporative emission components. The feedback signal should be low when the turned ON and high when turned Off. The following codes will be set if the above conditions are not met. P0444, P0445, P0447, P0448, P0452, P0453 P0446

This code can be caused by the canister closure valve (CCV) being either stuck closed or open.

CCV stuck open:A CCV is stuck open then there will be minimal tank depression when the leak test is performed. Addition check will be performed when the vehicle is being driven before the code is set.

CCV stuck closed:
Detection of a stuck closed CCV is implemented by detecting an excessively low tank pressure during normal purge. Detection of this fault will disable further purging

Additional checks for stuck CCV closed:
• Vehicle not stationary
• Load between 30 – 35%
• Purge Value >= 75%

Monitor: Until leak check is completed.
P0451

This code is set when the ECU detects abnormalities in the fuel tank vapour pressure sensor signal. The ECU analyses the filtered and unfiltered pressure signal at idle after a de-slosh period to determine if there is any difference, a big difference indicates as fault. The ECU also monitors the signal on gear changes to see if there is any pressure rise as a result of the fuel sloshing around.

Disable Criteria:
P0500 – Wheel speed sensor fault
Monitor: Until leak check is completed

Notes:
The MIL will be illuminated if the fault is present for 2 consecutive trips.

It sounds like you have a bad (or at least stuck) Purge Control Valve ...

Incidentally, the P0139 code indicated that you had a "slow" oxygen sensor (i.e. it was going bad)...

P0139
Set when the sensor fails to reach 650mV after 1.9 seconds of P.E or when the sensor fails to drop below 150mV after 5 seconds of DFCO ('06 M.Y.; Set when sensor fails to switch between 250mV and 650mV with sufficient rapidity).

Enable Criteria:
• Engine run time > 200 seconds
• Coolant temperature > 60°C (140°F)
• Open loop fuel control
• DFCO (Deceleration Fuel Cut Off) followed by idle operation for 'lean to rich' switch
• DFCO for 'rich to lean' switch

Disable Criteria:
P0116, P0117, P0118 – Coolant Temperature Sensor faults
P0201, P0202, P0203, P0204 – Injector faults
P0300, P0301, P0302, P0303, P0304 – Misfire faults
P1301, P1302 – Misfire faults causing emission or catalyst damage

Monitor: Continuous, until the test is either passed or failed

Potential failure modes:
• Check and rectify any pre catalyst sensor fault code, as they may be causing the fault code to be set
• Catalyst

[John C]

Thanks Tim

I have been trying to download from the Lotus site but the link to the Workshop manual seems to be down at the moment. (Yesterday)
I have managed to get hold of an owners manual and some info from Toyota.
Like most I'm miles from a dealer, part of the fun of ownership.
That's why I asked for the help, will try the Lotus site again today and I have sent them an e mail but still awaiting a reply.

I will keep you posted on my progress

Regards

John Coombs