Code No. 28 (Solenoid Valve—Egr, Vacuum Side); Code No. 29 (Solenoid Valve—Egr, Vent Side) - Mazda 626 MX-6 Workshop Manual

4 B TROUBLESHOOTING WITH SST
Code No. 28 (Solenoid valve—EGR, vacuum side)
Is there continuity between solenoid valve and en­
gine control unit?
Solenoid valve
B (WL wire)
Code No. 29 (Solenoid valve—EGR, vent side)
Are there poor connections in solenoid valve circuit?
Is there continuity of solenoid valve?
Is there battery voltage of RB wire of solenoid valve
connector?
Is there continuity between solenoid valve and en­
gine control unit?
Solenoid valve
B (LW wire)
4B-30
YES
Control unit
2N
YES PC: • Short circuit in wiring harness
YES
NO
YES
YES
Control unit
2M
YES
NOt PC: Open circuit in wiring harness from solenoid
valve to engine control unit
• Engine control unit malfunction
Repair or replace connector
NO
Replace solenoid valve
NO
PC: Open circuit in wiring harness from RB wire to
main relay (for engine control unit)
NO
PC: Open circuit in wiring harness from solenoid
valve to engine control unit
PC: • Short circuit in wiring harness
• Engine control unit malfunction
PC: Possible Cause
86U04B-020
86U04B-021