OBD2 Communication failure?
 

I took my car to the smog referee because I got a state ref ticket a while ago for header and exhaust. Finally got the chance to take it in to pass the car. While I got the certificate, I failed because there was an obd2 communication failure so I couldn't complete the test. On the paper I was given, it says "OBDII Monitors Not Ready" and then "Evaporative System and Oxygen Sensor" underneath. Everything else passed though.

I was on the OFT Stage 2 tune and made sure I flashed the car back to stock when I did. I did drive over 100 miles to make sure that the ECU was relearning.

I read online that it could be possible that the car is too new and that the system they used to smog my car (rollers) doesn't support the CAN BUS system that the car has? I could be totally wrong but I swear I remember seeing something like that online not too long ago.Honestly don't even know how this works lol

Whoever told you that was on drugs.

I don't know the specific conditions needed to fully complete a drive cycle for our cars but it sounds like you still need to drive it in a specific way in order for the evap system and o2 to complete their portion of the drive cycle. However, that should not cause a communication error. I would go back tomorrow to try again and see if you get a better reader or you completed the cycle by then. That would be my next step as far as troubleshooting goes if you don't have an obd2 scanner.

What's up thecarfilmer? We do emissions at the shop I manage. The problem you have is not from a lack of communication. If the vehicle's ecu could not communicate with the emissions machine, then the emissions machine would not know that your evap and o2 monitors were incomplete. Anytime you disconnect the battery, reset the ecu or clear codes from the ecu, the vehicle has to run through it's own series of self tests on emissions control systems. In order for it to run these tests, it wants to see some specific driving conditions met, sometimes those conditions have to be met multiple times for the monitor to complete. The culmination of the driving conditions for all of the self tests is referred to as a drivecycle. Not sure what the standard is in California, but in GA, a vehicle that is 2001 year model or newer can pass with one monitor incomplete.


Here are the drive patterns to complete the o2 sensor monitor:
CONFIRMATION DRIVING PATTERN


http://www.alldatapro.com/alldata/PR...6730/191557387

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON and turn the Techstream on.
3. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation) See: Powertrain Management\Computers and Control Systems\Testing and Inspection\Reading and Clearing Diagnostic Trouble Codes.
4. Turn the ignition switch off and wait for at least 30 seconds.
5. Turn the ignition switch to ON and turn the Techstream on.
6. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.
7. Perform the following the confirmation driving pattern.

CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.

1. Idle the engine for 10 seconds or more [A].
2. Accelerate the vehicle to 97 km/h (60 mph) or more within 20 seconds [B].
3. Drive the vehicle at 97 km/h (60 mph) or more for 20 seconds or more [C].
4. Release the accelerator pedal to Decelerate until the vehicle speed decreases to less than 64 km/h (40 mph) [D].

HINT
Release the accelerator pedal fully to perform the fuel-cut.

1. Drive the vehicle at 60 km/h (40 mph) or less for 20 seconds or more [E].
2. Accelerate the vehicle to 97 km/h (60 mph) or more within 10 seconds [F].
3. Release the accelerator pedal and stop the vehicle [G].

• 1. Enter the following menus: Powertrain / Engine / Trouble Codes.
  2. Read pending DTCs.

If you can not get this monitor to complete, you may have a problem with one of the o2 sensors.


Here are the Driving patterns for your Evap monitor:

1. KEY-OFF MONITOR CONFIRMATION

1. (a)

PreconditionsThe monitor will not run unless:

• The vehicle has been driven at 48 km/h (30 mph) or more for a total of 10 minutes or more.
• The fuel tank is less than 90% full.
• The engine coolant temperature is between 5°C and 45°C (41°F and 113°F).
• The intake air temperature is between 5°C and 50°C (41°F and 122°F).
• The vehicle remains stationary (the vehicle speed is 0 km/h [0 mph]).

(b)Monitor Conditions(1)Allow the engine to idle for at least 5 minutes.(2)Turn the ignition switch off and wait for 6 hours (8 or 10.5 hours)

wut

You have removed a catalytic converter, it's a miracle you didn't get hit on the visual inspection and they bothered to plug the scanner in at all. If the OBD2 port was not communicating it would not have printed out "Evaporative System and Oxygen Sensor" as the error code causing failure.

You need to reinstall the stock header with catalytic converter, keep the stock tune on, and clear the codes on the ECU before returning. You cannot pass California emissions without an OE or certified replacement catalytic converter in the header system.

If the smog ref gave it an ok on visual inspection, then he does not need to worry about this, he just has to get those monitors complete.

A decent obd/can scan tool or a Bluetooth dongle and the Torque App (for android) will make this process much easier. You need to be able to check the status of the readiness monitors. The Torque App is great for this because in the live data portion of the app, you can watch the status of the monitors in real time without waiting for the scan tool to refresh.

Yeah the whole exhaust was put back to stock

Ran into a similar issue, hope this helps someone.

Running OFT Stage 2 E85, took car to get it inspected and failed to connect to OBD2. Rolled back to stock map. Took it back to same shop and failed again. I even took it to a different shop but failed to connect there too.

I finally got it to pass after a week of running on stock map. The only thing that comes to mind is that I took it to the shop the same day I re-applied the stock map instead of driving it for ~100 miles.

:iono: