Wire and Component Test Using V.A.G1598/31 Test Box

Wire And Component Test Using V.A.G1598/31 Test Box

NOTE:







- V.A.G1598/31 test box is designed so that it can be simultaneously connected to the wiring harness at the Engine Control Module (ECM) and also to the ECM itself.
- This is advantageous because electronic engine control remains fully functional (e.g. measurement of signals with engine running) when the test box is attached.
- Relevant test procedures note whether Engine Control Module (ECM) should also be connected to the test box or not.
- Use the following for the test: V.A.G1526 portable multimeter or the V.A.G1715 multimeter and the V.A.G1527 voltage tester.
- Always use adapter cables from V.A.G1594 connector test kit for connecting special tools to the V.A.G1598/31 test box.

WARNING: To avoid damaging electronic components, set measuring range before connecting test leads and observe all test requirements.

Connect V.A.G1598/31 test box
- Switch ignition off.
- Remove right cover from plenum chamber.







- Open both bolts (arrows) and remove Engine Control Module (ECM) toward front.







To complicate accessibility to the harness connectors at Engine Control Module (ECM), Engine Control Module (ECM) -1- is screwed to a protective housing -4- via a locking mechanism -2- and snap-off screws -3-.

The thread of the snap-off screws is coated with locking compound to additionally complicate removal of the snap-off screws.

To be able to disconnect harness connectors from Engine Control Module (ECM) (e.g. when connecting test box or when replacing Engine Control Module), Engine Control Module (ECM) must be removed from protective housing. This procedure is described in the following.

The following equipment is required:







- Heat gun -1- (from VAS1978 Wiring Harness Repair Kit)
- Attachment nozzle -2- (also from VAS1978 Wiring Harness Repair Kit)
- Standard locking pliers

Procedure:

WARNING: To avoid damage (burning) of wire connections and harness connectors, insulation and control modules, the following work steps must be adhered to exactly. Observe operating instructions of heat gun.







- "Flip" Engine Control Module (ECM) with protective housing in direction of engine compartment so that the locking mechanism (item -2- in illustration) becomes visible, place a clean rag below the Engine Control Module (ECM) with protective housing.







- Perform adjustments on heat gun as shown in illustration, i.e., potentiometer for temperature selection -2- to maximum heat output and the two-stage switch for air flow - 3- to position 3.

NOTE: Next, the thread of locking mechanism in which the snap-off screws are threaded in are heated using the heat gun. This step lowers the inhibition effect of the locking compound on the thread of the snap-off screws, to ease the removal of the snap-off screws.

WARNING: When heating threads of locking mechanism, snap-off screws and components of protective housing are also heated intensely. Do not burn yourself on them.Also make sure that only the thread is heated if possible and no other components in the vicinity are heated. Cover these as necessary.







- Guide nozzle -1- of heat gun onto locking mechanism thread so that the nozzle "encloses" the thread. Let nozzle make contact steadily on upper end of protective housing.
- Switch on heat gun and heat thread for approx. 20 to 25 seconds.







- Then clamp bolt head -2- using locking pliers -1- and unscrew snap-off screw in direction of (arrow).

Procedure for the second snap-off screw is exactly the same. Be especially careful, because the control module connectors are located in the immediate vicinity.







- Guide nozzle -1- of heat gun onto locking mechanism thread again so that the nozzle "encloses" the thread. Let nozzle make contact steadily on upper end of protective housing.
- Switch on heat gun and heat thread for approx. 20 to 25 seconds.







- Then clamp bolt head -2- using locking pliers -1- and unscrew snap-off screw in direction of arrow.
Now Engine Control Module (ECM) can be detached from protective housing.
- Disengage connectors from Engine Control Module (ECM) and then disconnect the connectors.







- Connect V.A.G1598/31 test box to connector of wiring harness. Ground (GND) clip must be connected to Ground (GND). Relevant test procedures note whether Engine Control Module (ECM) should also be connected to the test box.
- Perform test as described in relevant repair sequence.

Installing Engine Control Module (ECM)
Installation is performed in reverse order, ECM must always be installed with the protective housing. New snap-off screws must be used.

Perform the following work after re-connecting Engine Control Module (ECM):
- Generate readiness code.

NOTE: In the first adaptation phase during engine basic setting, it is possible that idle will be rough and vehicle may shake lightly in drive mode.