2002 SAAB 9-3 smoke/turbo failure

RLONG

MEMBER
2002 SAAB 9-3
4 CYL
AWD
AUTOMATIC
119,000 MILES

I purchased a 2002 saab from a dealer as is. Car was smoking excessively with no turb boost apparent. I cleaned the oil pan and upper inside of engine to remove sludge some but not alot present. I replaced old turbo with a new factory turbo. Everything looked good and the car ran great for about 3000 miles. It now has little boost again and is smoking badly when it does boost and I back off. Sound like a bad turbo again, but I am not going to throw the money away if there is another issue I should be looking at? A turbo should last more than 3000 miles. The car started going into "limp mode" out of nowwhere about 3weeks ago, the idle will drop to about 500rpms and I have to dis connect battery terminal to restore idle. A code was set p1251 but my parts shop could not decode the number for me. Could all of this be related?

1 Reply

DAVE H

MECHANIC
13,383 POSTS

Hello.. thanks for the donation .. much appreciated

Try thoroughly cleaning the Throttle Body it may be sticking due to carbon deposits ?

DTC P1251: Throttle Motor. Full PWM in Closing Direction. NOTE. May set if Mechanism is not Reseted.

Fig. 280: Identifying Throttle Motor

NOTE:The system cannot close the throttle disc.

Fault symptoms
CHECK ENGINE.
Idling speed incorrect.
CRUISE CONTROL NOT WORKING.
Starting difficulties, especially when the engine is cold.
On-Board Diagnostics
Type of diagnosis:
Continuous. But interrupted when fault criteria fulfilled and will not restart until next driving cycle.
Enable criteria
Test 1: Engine running. Car in motion.
Test 2: Engine running for less than 5 s.
Fault criteria
Test 1 and Test 2: Throttle motor receiving 100% PWM in closing direction.
Dependents
None
System reaction to a fault
Throttle control goes into limp-home mode. The limp-home solenoid will be activated 5 times in succession each time the ignition is turned on until the fault has been rectified and the trouble codes cleared.
OK report
Accelerator pedal has been depressed at some time and then fully released. 120 s has expired since then without fault criteria being fulfilled.
Fault handling: (For more information, see FAULT HANDLING III, OTHER EMISSION-RELATED COMPONENTS AND FUNCTION).
CHECK ENGINE goes on immediately and can be turned off only by clearing the trouble codes.
Diagnostic help
A mechanical fault is preventing the throttle from closing.
Checking the wiring
Jiggle the wiring harness at several points and in different directions to detect intermittent breaks and short circuits. Observe the multimeter, diagnostic tool or test lamp during the check.