TJ. MFI #18 Injector Pulses Absent

TJ. MFI#18

MFI#18 Injector pulses absent




Fault message conditions:
If voltage has not been below 9 V for a certain amount of time, approx. 250 ms, the fault message is logged.
A fault message is not logged if fuel shut~off requirements are met - engine speed has been over 2200 rpm and then not dropped below 1100 rpm and the idle switch is on.

Causes of fault:
Break or grounding in the wiring between MFI#18 and the injectors.
No power supply to the injectors.
The suppressor relay is defective.

Fault symptoms:
The engine will not start.
If the fault is intermittent the engine will stop or engine speed will drop.

TJ1




Volvo ST, Test box
- Disconnect the ST in accordance with QA2. QA. Connecting The Volvo Scan Tool (ST)
- Connect the test box to MFI and check the GND points in accordance with P1-P2. P. Test Box, Signal Description
^ Continue with Checking the power supply TJ2.

TJ2




Checking the power supply
- Connect the control module to the test box.
- Install the fuse.
- Ignition on.
Connect a voltmeter between MFI#18 and MFI#17 (power GND).
The voltmeter should read battery voltage.

If this value is OK
^ check the control of #18 TJ3.

If the reading is incorrect
^ check the suppressor relay HC1. HC. Checking the Suppressor Relay

TJ3




Checking the control of #18
Connect a voltmeter between MFI#18 and MFI#35 (voltage).
- Operate the starter motor.
The voltmeter should read under 1 V.

If this value is OK
Intermittent fault.
^ Check the connections between MFI#18 and the injectors for loose contacts and intermittent grounding in accordance with NA5 and NA3. NA. Checking the Wiring
^ Check the wiring between MFI#18 and the suppressor relay via the injectors for loose contacts and intermittent grounding in accordance with NA5 and NA3. NA. Checking the Wiring

If the reading is incorrect
^ Try using a new control module.