P103

DTC P103:

EGR Valve Circuit:

CIRCUIT DESCRIPTION:
The brake booster vacuum sensor changes resistance based on the vacuum inside the brake booster. This diagnostic test checks for a vacuum sensor reading which would be caused by an open sensor or an open in CKT 474 or a short to ground on CKT 1726 (i.e. sensor voltage of 0.3 volts (-8 kPa VAC) or less). When the PCM detects a brake booster vacuum signal that is too low, Code P103 will set.

TEST CONDITION(S):
Test continuously.

FAILURE CONDITION(S):
Brake booster vacuum reading of 0.2 volt (-8 kPa) or less for 2 seconds.

ACTION TAKEN:
1. PCM turns "ON" the "SERVICE VEHICLE SOON" message.
2. IPC turns "ON" the "CHECK INFO CENTER" telltale.

NOTES ON FAULT TREE:
1. If the brake booster vacuum sensor is open PD84 should read -8 kPa or less. If it does not, then the sensor is not open.
2. If the brake booster vacuum sensor is open PD84 should read 82-84 kPa with pins "A" and "B" jumpered together.
3. Checking CKT 1726 for a short to ground between BBV and PCM.
4. Checking CKT 1726 for an open between BBV and PCM.