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P1842

Symptom: CHECK ENGINE indicator lamp (MIL) on. The system's emergency operation program has been activated. No signal for torque reduction results in harsh shifting.

P1842

TORQUE LIMITATION signal to fuel system, open circuit or shorting to ground.

Fault symptom

CHECK ENGINE indicator lamp (MIL) on. The system's emergency operation program has been activated. No signal for torque reduction results in harsh shifting.

Condition

Shorting to ground or open circuit.

Diagnostic help

The torque limitation function can be controlled with the diagnostics instrument. Select "ACTIVATE". Select "TORQUE LIMITATION". With the selector lever in position N and the engine running at more than 3000 rpm under no-load conditions, engine speed should momentarily drop to about 2500 rpm and then restabilize.

Check the wiring

Intermittent faults may occur as a result of temporary short circuits and breaks in the wiring. Jiggle the leads at several places and in different directions to reveal any faults in the wiring harness, including connectors. Observe the multimeter, test lamp or ISAT scan tool while carrying out this check.

Diagnostic procedure

1 Check the signal to the engine management system




- Plug a BOB into the transmission control module connector but do not connect the control module,

- Turn the ignition switch to the ON position.

- Take voltage and amperage readings across pins 13 and 22. Nominal voltage is about B+ (battery voltage) and amperage about 8 mA.


Are the readings correct?

yes

Continue with point 3.


no

Continue with point 2.


2 Check the wiring between the transmission control module and the engine control module


Check the continuity of the wiring between pin 13 of the transmission control module and pin 13 (Saab Trionic) or pin 51 (Motronic) of the engine control module.

Is the wiring OK?

yes

Continue fault diagnosis as described in Service Manual 2:7 "Engine management system" and then continue with point 3.


no

Rectify the fault and continue with point 3.


3 Final check


Clear the diagnostic trouble code. Drive the car on test at varying engine loads and speeds and obtain readouts of any diagnostic trouble codes that are generated.

Does the diagnostic trouble code recur?

yes

Continue with .


no

The remedial action taken was correct.