DTC P1456 and P1457 - Troubleshooting Update: Overview
June 9, 199898-045
Applies To: 1998 Accord - ALL
Service Manual Update: Troubleshooting DTC P1456 and P1457
The 1998 Accord Service Manual troubleshooting procedure for DTC P1456 and P1457 is incorrect. Make notes on service manual pages 11-7 and 11-124 to refer to this service bulletin.
Evaporative Emission Control System
Troubleshooting DTC P1456 and P1457
Please note that these are two-trip codes, once cleared, they cannot be reproduced in one trip. Also, certain specific driving and ambient conditions must occur before the PCM/ECM completes the system checks. Additional tests drives may still not meet the specific conditions needed to reproduce the code.
Therefore, follow these troubleshooting procedures carefully to ensure the integrity of the system and to confirm the cause of the problem or code.
NOTE:
Fresh fuel has a higher volatility that will create greater pressure/vacuum. The optimum condition for testing is fresh fuel and less than a full tank of gas. If possible, to assist in leak detection, add one gallon of fresh fuel to the tank (as long as it will not fill the tank), just before starting these procedures.
NOTICE
The fuel system is designed to allow specified maximum vacuum and pressure conditions. Do not deviate from the vacuum and pressure tests as indicated in these procedures. Excessive pressure/vacuum would damage the EVAP components or cause eventual fuel tank failure.