Auto Service Professional

OCT 2018

Magazine for the auto service professional

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62 A S P O c t o b e r 2 018 T e c h n i c a l S e r v i c e B u l l e t i n s FORD FORD GTDI STUMBLE Some 2013 Ford F-150 vehicles built on or before 9/18/2012 and equipped with a 3.5L GTDI (gaso- line turbocharged direct injection) Ecoboost en- gine may exhibit an intermittent stumble and/ or misfire on hard acceleration aer an extended drive at highway speed during humid/damp con- ditions. is could result in a steady or flashing MIL with DTC P0300, P0304, P0305, P0306, pri- marily for misfire. P0430 may also be present. If DTC P0430 is present, replace the le hand catalytic converter. If not, install a new CAC (charge air cooler). Refer to section 303-12 in the workshop manual. BUICK TRICKY VACUUM is bulletin applies to 2012/2013 Buick Regal vehicles with the MIL on and with DTC P0442 set as cur- rent or in history (EVAP system small leak canister vent solenoid valve not sating under vacuum). During the EVAP system test for P0442, the EVAP Vent Solenoid (CVS) valve will be in a vacuum condition. During normal diagnostics, the system is pressurized to no more than 13-inches (0.5 psi), so a leak under vacuum may not be detected. It is possible for the CVS to seal when pressurized but may leak under vacuum. is leak may be intermittent as the seal may rotate when the CVS is cycled. is leak may also only be present in colder ambient temperature. Do not replace the EVAP canister assembly for this concern unless it fails the leak test. e diffi- culty to determining the cause of the EVAP leak re- sults in improper repairs and potential comebacks. If no leak is found aer following system testing instructions in the service manual, follow these additional steps: 1. Connect the scan tool to the vehicle and command the EVAP system (vent solenoid valve) closed. 2. Start the engine and monitor the fuel tank pressure sensor out- put value for approximately two minutes. 3. Open the purge valve by commanding some per- centage of purge. 4. Ensure that the canister vent solenoid is closed and monitor the FTP sensor for a vacuum to de- velop (purge and seal). 5. If vacuum does not develop, refer to purge valve diagnostics. 6. If vacuum does develop, command the EVAP system closed (purge and seal) and monitor for vacuum decay. 7. If a significant leakdown is not found, cycle the CVS and retest. 8. If a significant leakdown rate is found, replace the CVS with P/N 22740537. ■ CHEVROLET A BAFFLING CONCERN is bulletin applies to 2009-2013 Chevy Tra- verse vehicles. e fuel gauge may not go to the empty mark and the engine runs out of fuel. You may also hear a fuel slosh or noise from the fuel tank area when braking or accelerating from a stop. ere is a baffle in the fuel tank that may have come loose and is now lying in the bottom of the tank. is may prevent the fuel level sensor from travelling to the bottom of the tank. This baff le may become dis- lodged aer the vehicle has been in an accident. If diagnostics indicates replacing the fuel level sensor, inspect the fuel tank for a baffle that may have come loose before replacing any parts. e baffle may have become lodged at either end of the tank, so it may be necessary to tip the tank in both directions to locate the loose baffle. If the baffle is found in the bottom of the tank, it will be necessary to replace the fuel tank.

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