Deceleration Fuel Shutoff
- Ensure engine is at normal operating temperature and no fault codes are stored in ECU memory. Using a digital voltmeter and Adapter (VW 1315A/1), check voltage at differential pressure regulator.
- Connect voltmeter to differential pressure regulator using adapter. See Figure
. Turn ignition on. Control voltage must be positive (+). If voltage is negative (-), reverse test leads.
- Start engine. Raise engine speed to 3000 RPM and release throttle. Control voltage should switch to negative (-) momentarily. If system fails test, perform electrical tests. See Figure
and the CIS-MOTRONIC VOLTAGE & RESISTANCE TESTS
table. If system electrical tests are okay, replace ECU and clear fault codes.
CIS-MOTRONIC VOLTAGE & RESISTANCE TESTS
| Test Step |
Terminals |
Test Conditions |
Test Values |
| No. 1 |
14 & 35 |
Ignition ON |
About Battery Voltage |
| No. 2 |
17 & 35 |
Ignition ON |
About Battery Voltage |
| No. 3 |
32 & 35 |
Ignition & A/C ON |
About Battery Voltage |
| No. 4 |
33 & 35 |
Ignition & A/C ON |
Battery Volts Minus 1 |
| No. 5 |
19 & 35 |
Ignition ON |
About Battery Voltage |
| No. 6 |
13 & 35 |
Insert Fuel |
Fault Indicator |
| " |
" |
Relay Fuse |
Must Light |
| " |
" |
Ignition ON |
Fault Indicator Must Light |
| No. 7 |
4 & 5 |
Ignition OFF |
15-25 Ohms |
| No. 8 |
3 & 35 |
Ignition OFF |
2500 Ohms @ 68°F (20°C) |
| " |
" |
" |
200 Ohms @ 212°F (100°C) |
| No. 9 |
31 & 35 |
Throttle Closed |
Open (No Continuity) |
| " |
" |
Throttle Wide Open |
Continuity |
| No. 10 |
28 & 35 |
Throttle Closed & Open |
Continuity |
| No. 11 |
18 & 35 |
" |
Continuity |
| No. 12 |
13 & 35 |
Insert Fuel Relay Fuse |
Continuity |
| " |
13 & 35 |
Ground Test Connector |
Continuity |
| No. 13 |
14 & 16 |
Cold Start Valve Test |
About 10 Ohms |
| No. 14 |
14 & 15 |
Charcoal Canister Valve Test |
30-60 Ohms |
| No. 15 |
" |
Unplug Hall Effect Sensor Connector |
" |
| " |
30 & 35 |
Terminals 1 & 2 To Sensor |
Continuity |
| " |
30 & 21 |
Terminals 2 & 3 To Sensor |
Continuity |
| No. 16 |
11 & 35 |
Remove Terminal @ Power Output Stage |
" |
| " |
" |
Of Coil. Ground Center Contact |
Continuity |
| No. 17 |
" |
Disconnect Knock Sensor Connector |
Open |
| " |
6 & 8 |
Connect Terminals 1 & 2 |
Continuity |
| " |
" |
Connect Terminals 1 & 3 |
Continuity |
| No. 18 |
7 & 35 |
Disconnect O2 Connector & Gnd |
Continuity |
| No. 19 |
23 & 26 |
Sensor Plate @ Rest |
About 5000 Ohms |
| No. 20 |
26 & 35 |
Sensor Plate @ Rest |
About 4000 Ohms |
| No. 21 |
34 & 35 |
Man. Trans. |
Continuity |
| " |
" |
Auto. Trans. In "P" Or "N" |
Open |
| No. 22 |
12 & 35 |
Remove Fuel Pump Relay & Ground |
" |
| " |
" |
Pin 47 Of Fuse Panel Relay |
Continuity |