One problem related to catalytic convertor has been reported for the 2004 Cadillac CTS. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 Cadillac CTS based on all problems reported for the 2004 CTS.
Emission test failure. 2004 Cadillac Cts. 875 miles on odometer just picked up from dealer brought back following day for inspection sticker,would not pass emissions test. Told by dealer vehicle had blocked catalytic converter and need replacement.