
Diagnostic procedure

Dtc b1877, b1878, b1879, b1885
Dtc b1884, b1890Mazda 6 Service Manual: Bonnet switch inspection
Note
Bonnet switch has a built-in bonnet lock.
1. Open the bonnet.
2. Disconnect the negative battery cable.
3. Remove the radiator grille.
4. Disconnect the bonnet switch connector.
5. Check the continuity between the bonnet switch terminals A and B using an
ohmmeter.
If there is ...
Mazda 6 Service Manual: Procedures for determining the location of a malfunction
System Wiring Diadram
PCM
1. Check the display of DTC U0121 and/or U0155, using the SST (WDS or
equivalent). (See DTC TABLE.)
2. Referring to the following table, determine the malfunctioning part of the
CAN system.
ABS/TCS HU/CM or DSC HU/CM
1. Accec and monitor the PCM MSG and IC MSGo ...