ECM - DTC's P0443 & P0441 Sert
12/31/9617/02/96/US
SUBJECT:
PRIDE - Canister Purge Control Valve (CANPV) Diagnosis
MODEL:
Range Rover 4.0/4.6
Discovery
AFFECTED VEHICLES:
LP 1995 - 1996 MY
LH
LJ 1996 MY
LD
DETAIL
The charcoal canister is designed to collect the fuel vapor generated in the fuel tank and transfer the vapor into the air stream entering the engine. This ensures that the fuel vapor is burned during the combustion process and not allowed to escape into the atmosphere. The Charcoal in the canister absorbs the fuel vapor to prevent condensation within the canister. The vapor is allowed to enter the air steam in a Controlled manner through the normally closed purge valve. When the canister purge valve (CANPV) is activated, the valve is opened and closed in rapid succession (modulated) to introduce fuel vapor into the air stream. The purge valve is modulated to prevent the introduction of large amounts of air that would be introduced if the purge valve was left fully opened.
When the CANPV is modulating, the system monitors the oxygen sensor signal to determine if there is any vapor in the canister. If the oxygen sensor signal shows a lean condition (no vapor in canister), the system turns off the purge valve.
When the vehicle is first turned on, the GEMS module performs a check of the purge valve to verify that is functioning electrically. If the system detects an open or short condition, it will set DTC P0443. If the valve is functioning properly electrically, the system can determine if the valve is operating mechanically by modulating the valve when the engine is running. Failure of the mechanical test will set DTC P0441. Follow the procedures outlined below to troubleshoot DTC codes P0443 and P0441.
The diagnostic steps and repair procedures detailed in this bulletin were developed as an element of the Land Rover Way OPERATION PRIDE. This TIB provides a library location for PRIDE information within the Land Rover North America technical literature system.
ACTION REQUIRED
Upon customer complaint for the symptoms outlined, perform the specified repairs.
PARTS INFORMATION
Range Rover:
ESR3001- Purge Valve
Discovery:
ESR3480 (1996 model year)
ESR4017 (1996.5 model year)
PROCEDURE
Perform the diagnostic procedures and repairs outlined in this bulletin for the repair of Purge Control Valve.
DTC P0443
1. Disconnect the electrical connector from the purge control valve.
2. Measure the resistance of the valve. The resistance should be approximately 45 ohms at room temperature (20°C, 68°F).
3. If the resistance is incorrect, replace the purge control valve. If the resistance is normal, check the wiring harness for an open or short.
DTC P0441
1. Start the vehicle and allow the engine to reach operating temperature.
2. Check the purge control valve by listening to or feeling the purge valve to check for modulation.
3. Disconnect the hose that runs between the purge control valve and the charcoal canister at the charcoal canister (quick fit connector). Check for vacuum while the purge valve is modulating.
4. If there is no vacuum, the valve is stuck closed; replace the purge control valve. If there is vacuum, go to step 5.
5. Disconnect the electrical connector from the purge control valve while the valve is still modulating. Check for vacuum at the hose that was disconnected in step 3. If there is vacuum, the purge control valve is stuck open and must be replaced.
HOSE INSPECTION
1. Lift hood and examine the full length of the purge hoses.
2. Check that none of the hoses have been bent in a manner that would restrict the flow of vapors to the canister. See figure 1 for the proper routing of the hoses in the vicinity of the canister.
3. If the hoses are found to be kinked they must be replaced.
4. Use care when replacing the hose(s) so that the individual components are not damaged.
5. Hook up TestBook and clear any codes that may have been set.
WARRANTY:
Normal warranty procedures and policies apply.
COMP.CODE:
SR0:
17.15.39 Time 0.25 hr.
Renew canister purge valve.