Test sequence

WARNING: This page is about a different car, the 1999 Volkswagen Jetta, 1998 Volkswagen Jetta, and 1997 Volkswagen Jetta. However, it is still accessible from the selected car via links, so may be relevant.

Connect VAG1551 or VAG1552 scan tool.
1. See VAG1551 SCAN TOOL (ST), CONNECTING
Start engine and let idle.

Press buttons -0- and -1- to insert the "Engine Electronics" address word 01.

Indicated on display

Fig 1: Scan Tool Display - Checking Vehicle Speed Signal (1 Of 3)

Press buttons -0- and -8- to select "Read Measuring Value Block" function 08.
Press -Q- button to confirm input.

Indicated on display

Fig 2: Scan Tool Display - Checking Vehicle Speed Signal (2 Of 3)

Press buttons -0-, -0- and -6- to input display group no. 6 (006).
Press -Q- button to confirm input.

Indicated on display (1 to 4 = display fields)

Fig 3: Scan Tool Display - Checking Vehicle Speed Signal (3 Of 3)

Road test and observe display during drive.
CAUTION: When "on the road" measurements are required for diagnosis, for obvious safety reasons, always use a second technician to take the instrument readings.
Check value in display field 1.
Specification: approx. equal to speedometer display

If there is no speed indicated:

Switch ignition off.
Connect VAG1598/18 test box to Diesel DFI ECM connector.

Fig 4: Connecting VAG1598/18 Test Box To Diesel DFI ECM Connector
Check wiring for continuity or short circuit between test box socket 43 and instrument cluster wiring.
Using wiring diagrams, individually determine all additional speed signal "users" (e.g. radio, automatic transmission, A/C etc.), rule out each one as a source of interference and repeat check each time until cause has been established.
Display readiness code, see READINESS CODE, DISPLAYING .

If DTC memory was erased:

Create readiness code again, see READINESS CODE, SETTING (UP TO M.Y. 1997) .