Browse Prior Art Database

ONBOARD ARBITRATION OF ENGINE LEAN DTCS P2196/P2198

IP.com Disclosure Number: IPCOM000234979D
Publication Date: 2014-Feb-20
Document File: 1 page(s) / 236K

Publishing Venue

The IP.com Prior Art Database

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 55% of the total text.

Page 01 of 1

ONBOARD ARBITRATION OF ENGINE LEAN DTCS P2196/P2198

Vehicles sold in North America are required to perform diagnostics on various powertrain subsystems. One such subsystem is the Evap shown below. For federal states, the Evap system is monitored for a leak size of 0.04". For green states, the system is monitored for a leak size of 0.02". The Evap leak monitor does not execute all the time. Only when certain vehicle and environmental conditions are suitable does the monitor execute. Conditions include fuel level between 15% and 85%, ambient temperature between 40F and 95F and (BP) Altitude < 8500 feet. If a leak is present at the CPV valve, the Evap monitor may not flag it in a timely manner and instead the unmetered air going into the intake from the leaky CPV triggers a "lean" condition (high A/F ratio) OBD diagnostic trouble code (DTC). A P2196 DTC indicates a lean condition for bank 1 and P2198 DTC indicates a lean condition for bank 2. If the engine is running lean, there could be many causes. P2196/P2198 codes are difficult to troubleshoot with offboard diagnostics. It assists diagnostics at the dealership if the onboard diagnostic is able to better pinpoint the root cause of P2196/P2198.

Method

This method helps arbitrate the root cause of the P2196/P2198 codes through onboard diagnostics as opposed to time-consuming and expensive dealership offboard diagnostics. A leaky CPV test is already a part of the Evap monitor, however, it can go months without runn...