On/Off Ratio Output
- Turn ignition off. Perform pretest conditions. See PRETEST CONDITIONS. If diagnosing a Federal vehicle, go to step 3). If diagnosing a California vehicle, turn ignition on. Press non-locking switch, located on diagnostic connector in right rear corner of engine compartment, for 2-4 seconds. See Fig 1 .
- CIS-E control unit will begin flashing LED light on diagnostic connector. See Fig 1
. Wait for LED to stop flashing. When LED illuminates constantly, press non-locking switch again for 2-4 seconds. Pressing non-locking switch puts CIS-E control unit into on/off ratio output mode.
NOTE: Limited diagnostic information is available for 190E 2.6L.
- Connect On/Off Ratio Tester (909 589 00 21 00) to diagnostic connector located on left fender apron. See Fig 1 . Start engine. Read on/off ratio. Turn ignition off. On 6-cylinder vehicles, see CIS-E (2.6L) under ON/OFF RATIO IDENTIFICATION. On 4-cylinder vehicles, before diagnosing on/off ratio readout, disconnect on/off ratio tester. Connect 25-Pin Test Cable (124 589 33 63 00) between CIS-E control unit and vehicle wiring harness.
- Connect Contact Box (124 589 00 21 00) to 25-pin test cable. See Fig 2 . See ON/OFF RATIO DIAGNOSIS for testing. If no on/off ratio is output, see NO ON/OFF RATIO OUTPUT under ON/OFF RATIO DIAGNOSIS.