P1402 Buick EGR Function Open

P1403 Buick Exhaust Gas Recirculation System Valve 1

Possible causes
– Faulty Diagnostic Module Tank Leakage (DMTL)
– Diagnostic Module Tank Leakage harness is open or shorted
– Diagnostic Module Tank Leakage circuit poor electrical connection
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
P1403 Buick Description

The heated DMTL (Diagnostic Module Tank Leakage) is used to monitor the evaporative system for leaks. The diagnostic module consists of an air filter, an heating element, an electrical driven air pump, a change-over valve. In switched off condition the fuel tank breathes through the canister, the changeover valve and the air filter. For purging the canister, the purge control valve is opened and fresh air-flows via air filter, changeover valve and canister into the intake manifold.

Buick Vehicle:Buick Regal – ?Buick Riviera – ?Buick LaCrosse – ?David Dunbar Buick – Buick Century – Buick LaCrosse – Buick LeSabre – Buick Lucerne – Buick Park Avenue – Buick Regal – Buick Verano – Buick Enclave – Buick Encore – Buick Rainier – Buick Rendezvous – Buick Terraza – Buick Riviera