Rate-Of-Turn Sensor: Diagnosis/Troubleshooting

DIAGNOSIS/TROUBLESHOOTING - FAULT CODE 4420

Work instruction			Display OK	If not OK
1	Check fault memory	Read out PSM fault memory with the Porsche System Tester II9588	Fault code entries 4400, 4420 and 4440 Step 2	Fault code entry 4420 only Step 5
2	Check positive supply to sensors for open circuit	Ignition off Pull plug off the rate-of-turn sensor Ignition on Measure voltage between pin 3 of rate-of-turn sensor plug and ground	> 11 V Step 3	Open circuit between pin 39 of PSM control unit plug and pin 3 of rate-of-turn sensor plug Repair wiring harness End
3	Check ground supply line to sensors for short circuit to B+	Ignition off Pull plug off PSM control unit Ignition on Measure voltage between pin 6 of rate-of-turn sensor plug and ground	< 0.3 V Step 4	Short circuit to B+ between pin 21 of PSM control unit plug and pin 6 of rate-of-turn sensor Repair wiring harness End
4	Check ground supply line for open circuit	Ignition off Measure resistance between pin 6 of rate-of-turn sensor plug and ground	< 5 Step 5	Open circuit between pin 21 of PSM control unit plug and pin 6 of rate-of-turn sensor plug Repair wiring harness End
5	Visual inspection	Check installation position of rate-of-turn sensor	Step 6	Install rate-of-turn sensor correctly End
6	Check signal leads of rate-of-turn sensor for short circuit to B+	Ignition off Pull plug off PSM control unit Pull plug off rate-of-turn sensor Ignition on Measure voltage between pin 1 of rate-of-turn sensor plug and ground Measure voltage between pin 2 of rate-of-turn sensor plug and ground Measure voltage between pin 4 of rate-of-turn sensor plug and ground	< 0.3 V Step 7	Short circuit to B+ between pin 10, pin 9 or pin 41 of PSM control unit plug and pin 1, pin 2 or pin 4 of rate-of-turn sensor respectively Repair wiring harness End
7	Check signal leads of rate-of-turn sensor for short circuit to ground	Ignition off Measure resistance between pin 1 of rate-of-turn sensor plug and ground Measure resistance between pin 2 of rate-of-turn sensor plug and ground Measure resistance between pin 4 of rate-of-turn sensor plug and ground	< 5 Step 8	Short circuit to ground between pin 10, pin 9 or pin 41 of PSM control unit plug and pin 1, pin 2 or pin 4 of speed sensor respectively Repair wiring harness End
8	Check signal leads of rate-of-turn sensor for open circuit	Ignition off Measure resistance between pin 1 of rate-of-turn sensor plug and pin 10 of PSM control unit plug Measure resistance between pin 2 of rate-of-turn sensor plug and pin 9 of PSM control unit plug Measure resistance between pin 4 of rate-of-turn sensor plug	< 5 Step 9	Open circuit between pin 10, pin 9 or pin 41 of PSM control unit plug and pin 1, pin 2 or pin 4 of rate-of-turn sensor plug respectively Repair wiring harness End
9	Replace rate-of-turn sensor		End