Open Issue Diagnosis Of Open And Short Circuit

Open Issue: Diagnosis Of Open And Short Circuit Faults With Freeze Frame Data For OBD-I Grade A Proposal By India

Background • EPPR 15 -05 Slide 5, India proposal to delete Need for FFD for Grade A. • EPPR 15 -13 Japan Proposal slide 7 on FFD requirement for Grade A • Discussion during EPPR 15 on this point and need for more data from India.

Data generation • Based on the request at EPPR 15, India collected data on two vehicles. • Both vehicles had Engine Controller (ECU) from different manufacturer • Both ECU’s are compliant to OBD I fully • Faults were created in both vehicles in different sensors at two different operating points

ECU Freeze Frame data • ECU Freeze Frame data captured during open and short circuit faults of sensors like Engine temperature sensor, Throttle Position Sensor and Lambda sensor for ECUs from two different manufacturers • Freeze frame data also captured at different engine speeds to identify the possible link between Freeze Frame data and the root cause of faults.

Manufacturer 1 ECU Freeze Frame Data Engine Temperature Sensor short

Manufacturer 1 ECU Freeze Frame Data Engine Temperature Sensor short

Manufacturer 1 ECU Freeze Frame Data Engine Temperature Sensor open

Manufacturer 1 ECU Freeze Frame Data Engine Temperature Sensor open

Manufacturer 1 ECU Freeze Frame Data O 2 Sensor open

Manufacturer 1 ECU Freeze Frame Data O 2 Sensor open

Manufacturer 1 ECU Freeze Frame Data O 2 Sensor heater short

Manufacturer 1 ECU Freeze Frame Data O 2 Sensor heater short

Manufacturer 1 ECU Freeze Frame Data TPS Open

Manufacturer 1 ECU Freeze Frame Data TPS Open

Manufacturer 1 ECU Freeze Frame Data TPS Short

Manufacturer 1 ECU Freeze Frame Data TPS Short

Manufacturer 1 ECU Freeze Frame Data Injector Open

Manufacturer 1 ECU Freeze Frame Data Injector Open

Manufacturer 1 ECU Freeze Frame Data Injector Short

Manufacturer 1 ECU Freeze Frame Data Injector Short

Manufacturer 2 ECU Freeze Frame Data Engine Temperature Sensor short

Manufacturer 2 ECU Freeze Frame Data Engine Temperature Sensor open

Manufacturer 2 ECU Freeze Frame Data Engine Temperature Sensor open

Manufacturer 2 ECU Freeze Frame Data TPS Open

Manufacturer 2 ECU Freeze Frame Data TPS Open

Manufacturer 2 ECU Freeze Frame Data TPS Short

Manufacturer 2 ECU Freeze Frame Data Injector Open

Manufacturer 2 ECU Freeze Frame Data Injector Short

Conclusions • Freeze frame data captured during open and short circuit faults of sensors at different engine speeds does not have sufficient information to identify cause for fault • Freeze frame data will not help in failure cause analysis for open and short circuit faults • Hence freeze frame data need not be mandatory for OBD I Grade A