On the older Honda system, P1457 identifies leakage or failed pressure behavior on the canister side; P1456 identifies the fuel-tank side. Bulletin 99-075 applies Procedure B specifically to 1998–2001 CR-V and updates its HDS, vacuum and component-isolation tests. That means a gas cap is not the default P1457 repair. Inspect the canister plumbing, bypass/vent and purge valves, verify fuel-tank-pressure sensor behavior and section the system. A valve that clicks electrically can still leak or restrict flow mechanically.
Match the symptom
Select the closest observation. The result changes the first test; it does not name a part to replace.
Use bulletin 99-075 Procedure B, not the Accord/Pilot layout.
What can set P1457—and how to separate it
The order below is evidence-driven, not a universal probability ranking. Vehicle year, repair history, companion codes and the operating condition in freeze frame change where diagnosis should begin.
| Possible cause | Evidence that supports it | First useful test |
|---|---|---|
| Canister-side hose leak or wrong routing | Visual/sectional smoke result | Compare routing and low-pressure smoke |
| Bypass or vent-shut valve leakage | Fails Honda vacuum-hold/command test | Individual valve test |
| Purge valve does not seal | Manifold vacuum reaches EVAP while commanded closed | Closed-state sealing test |
| Canister/two-way valve fault | Other sections pass but pressure behavior fails | Procedure B isolation |
| FTP sensor/circuit bias | Atmospheric/commanded values implausible | Reference, signal and pressure comparison |
The code already narrows the system
Honda split older EVAP monitoring into tank-side and canister-side regions.
Ignoring that split leads to repeated caps and missed valve or hose faults.
A pressure result can fail without a hole
The monitor expects valves to route and seal vapor in a timed sequence.
A restricted or leaking valve can imitate a physical opening.
Procedure B is CR-V-specific
Bulletin 99-075 groups the early CR-V with Civic for this layout.
The Accord/Pilot Procedure A uses different steps and should not be substituted.
Save these scan-data clues
Freeze frame is a snapshot of conditions when the PCM matured the fault. It can distinguish an idle-only problem from a load, cold-start or monitor-completion problem. Clearing first throws that context away.
- Fuel level and ambient/soak temperature
- P1456 and circuit companions
- FTP sensor voltage/pressure
- Purge/vent command and actual sealing
- Recent tank/canister/rear-body work
- Hose routing and water/corrosion evidence
A practical diagnostic workflow
- 01Confirm model-year system
The bulletin's CR-V procedure applies to 1998–2001.
- 02Keep P1456 and P1457 separate
P1457 directs attention to the canister side, not automatically the cap.
- 03Inspect hoses and valves
Check routing, cracks, water intrusion and canister fittings.
- 04Test sealing, not just clicking
Apply specified vacuum and commands to prove mechanical closure and flow.
- 05Section with safe smoke/vacuum
Use EVAP-regulated equipment and Honda's sequence.
- 06Complete the monitor
Verify repair through the service-bay or drive procedure.
Do not sell a gas cap as a certain P1457 fix and do not condemn the canister without isolating valves and hoses. Never apply unregulated shop air to a fuel-vapor system.
Why the model year changes the test
CR-V diagnostics span the first-generation B20, K24-powered second through fourth generations, 1.5L turbo and 2.4L fifth-generation versions, newer 1.5L turbo models and 2.0L hybrid systems. AWD does not create another engine bank, but engine management, direct injection, turbo plumbing, EVAP packaging, VTEC oil hardware and hybrid operating modes change. Confirm the VIN, market, engine, build plant, emissions label and current Honda campaign status before selecting a flowchart or part.
- 99-075 Procedure B lists 1998–2001 CR-V.
- P1457 is canister-side; P1456 is fuel-tank-side on this generation.
- Later CR-Vs generally use generic P044x codes and different layouts.
- Valve sound alone does not establish vacuum sealing or flow.
P1457 FAQ
Is P1457 a loose gas-cap code?+
Not primarily; Honda defines it as canister-side leakage.
Which CR-V years are in 99-075?+
1998–2001.
Can I drive?+
Usually briefly without odor or visible fuel.
What is P1456?+
It points to the tank side on this older strategy.
Can a clicking valve be faulty?+
Yes. It may leak or be restricted despite clicking.
Can smoke find the leak?+
Often, when safely regulated and the system is sectioned.
Should I replace the canister?+
Only after hoses, valves and pressure sensing are tested.
What confirms repair?+
Correct pressure behavior and a completed EVAP monitor.
Ford diagnostic references
These documents explain Ford monitor operation. Exact pinpoint tests, connector views and specifications must be selected for the truck's VIN and model year in current service information.
01Honda Service Bulletin 99-075 — 1998–2001 CR-V P1456/P1457Procedure B separates tank-side P1456 from canister-side P1457 and provides Honda vacuum/FTP tests↗02Honda ServiceExpressHonda VIN-specific service information, DTC flowcharts, wiring and service publications↗03Honda Owners — CR-V manualsOfficial model-year warnings, fuel, maintenance and operating information↗