Notes On Flow Chart

Circled numbers in flow chart correspond to the following numbers:

See NOTES ON INTERMITTENTS under TESTING & DIAGNOSIS.
A short to ground in circuit 1117 may damage the windings in the solenoid and create an open.

CAUTION: DO NOT backprobe connector terminals at position sensors or dampers.

NOTE: After repairs, clear codes and verify system operation.

Fig 1: CODE S018 Schematic

Courtesy of GENERAL MOTORS CORP.

Fig 2: CODE S018 Flow Chart

Courtesy of GENERAL MOTORS CORP.