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Mark N
Mark N, Saab Master Technician
Category: Saab
Satisfied Customers: 117
Experience:  30+ years experience on all models of Saabs!
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1999 SAAB 9-5 2.3T, Auto, 120k miles. Getting intermittent

Customer Question

1999 SAAB 9-5 2.3T, Auto, 120k miles. Getting intermittent P1300 and P0300 once the car is warmed up and driving, the codes start with sudden jerky hesitation usually taking off the full stop, easing off the accelerator smooths things out. No misfire when
idling, or under light acceleration or under sub WOT when cold.
Submitted: 1 year ago.
Category: Saab
Customer: replied 1 year ago.
Things attempted thus far:New DIC
New Plugs
New PVC all around
New Turbo
Fresh oil 15w-40
New Fuel Pump
New BatteryCompression is 1- 200, 2-200, 3-200, 4-205. Fuel pressure was correct dont recall the exact numbers.
Expert:  Jim replied 1 year ago.

The problem you are experiencing is usually caused by the ignition cassettes or engine speed sensor, in order to isolate the problem

down the following test will need to be done,

Test for power to the ignition cassettes on pin 10 (Green/Black). Should have battery voltage with the ignition on or starting.

Pin 6 (Black) should have constant ground.

Pins 1, 2 and 3 on each cassette are the input coil trigger signals from the Trionic Engine Control Module (ECM). A lab scope will show a 12V reference with a square-wave pulse to ground as the signal. A logic probe or other low-voltage Light Emitting Diode (LED) test light will show alternating Red (power) and Green (ground) lights during cranking.

If power, ground and signal inputs are good, replace the ignition cassette.

If signal inputs (ground pulses) are missing, test the engine speed sensor output between the Yellow and the Black wires. It should produce an AC voltage signal during cranking. A meter should show 1V AC or higher and a lab scope should show a sine-wave pattern, 2V peak-to-peak or higher.

Customer: replied 1 year ago.
OK, I dont have an access to a lab scope but I do have 2 ignition cassettes to play with - one that came on the car and a brand new one I just put on and both are behaving identically which leads me to believe the problem is elsewhere. Where is the engine speed sensor located ?
Expert:  Jim replied 1 year ago.

They use the rear wheel sensors, I am 99% sure they are using the left rear wheel sensor as the engine speed sensor, can confirm that Monday when I get back to work.

Customer: replied 1 year ago.
Ok, does the same sensor report to the speedo ?
Customer: replied 1 year ago.
Any update ?