P0300 on Saab
Random/Multiple Cylinder Misfire Detected
P0300 on Saab vehicles indicates random/multiple cylinder misfire detected. Au7o has documented this code across 2 Saab models — most commonly on 9-3, 9-5. P0300 means the engine computer detected misfires occurring randomly or across multiple cylinders rather than in one specific cylinder. A misfire is when a cylinder fails to ignite its fuel-air mixture properly, which the computer senses through small fluctuations in crankshaft speed. Because it's not isolated to one cylinder, the cause is usually something that affects the whole engine — like fuel, air, or ignition system problems — rather than a single coil or plug. Persistent or heavy misfiring wastes fuel, runs rough, and can damage the catalytic converter, which is why a flashing check engine light should be taken seriously. Typical repair costs on Saab range from $80 to $600, depending on the specific model and root cause.
Common Causes of P0300
- •Worn or fouled spark plugs (across cylinders)
- •Vacuum or intake air leak
- •Weak fuel pump, clogged fuel filter, or low fuel pressure
- •Failing ignition coils or worn spark plug wires
- •Dirty or faulty mass airflow (MAF) sensor
- •Clogged or dirty fuel injectors
- •Faulty crankshaft/camshaft position sensor
- •Low compression or EGR/PCV system faults
P0300 on Saab by Model
Saab 9-3(1 issue)
- 9-3 Direct Ignition Cassette (DIC) Failure1999-2011
The Saab Direct Ignition Cassette — single integrated unit covering all four spark plugs — is a well-known wear item across 9-3 (and 9-5) from 1999 through end of production. Symptoms: misfire (often cylinder-specific then random), reduced power, check engine light. Failure rate climbs sharply after 80,000 miles. Saab DIC heat-shielding cracks; rubber boots fail.
Saab 9-5(2 issues)
- 9-5 Direct Ignition Cassette (DIC) Failure1999-2009
Same DIC failure mode as 9-3 — 1999-2009 9-5 with the B235 2.3L turbo (Linear/Arc/Vector NA variants are B205) suffers DIC degradation. Saab dealers used to stock these by the dozen. Often the first part to fail on a high-mileage 9-5.
- Direct Ignition Cassette (DIC) Failure1999-2009
The Direct Ignition Cassette, which sits directly on top of the spark plugs and combines the coils into one unit, is a frequent failure point on the four-cylinder cars. Underhood heat and valve-cover gasket oil leaks contaminating the coil pack degrade the cassette over time, causing misfires, rough idle, hard starting and stalling. A failed cassette typically has a burnt smell and discoloration around the plug boots.
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View P0300 across all makes →Frequently Asked Questions
What does P0300 mean on Saab?▼
P0300 stands for "Random/Multiple Cylinder Misfire Detected." P0300 means the engine computer detected misfires occurring randomly or across multiple cylinders rather than in one specific cylinder. A misfire is when a cylinder fails to ignite its fuel-air mixture properly, which the computer senses through small fluctuations in crankshaft speed. Because it's not isolated to one cylinder, the cause is usually something that affects the whole engine — like fuel, air, or ignition system problems — rather than a single coil or plug. Persistent or heavy misfiring wastes fuel, runs rough, and can damage the catalytic converter, which is why a flashing check engine light should be taken seriously. On Saab specifically, this code is documented across 2 models.
What causes P0300 on Saab vehicles?▼
Common causes on Saab: Worn or fouled spark plugs (across cylinders), Vacuum or intake air leak, Weak fuel pump, clogged fuel filter, or low fuel pressure, Failing ignition coils or worn spark plug wires, Dirty or faulty mass airflow (MAF) sensor. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0300 on a Saab?▼
Repair costs on Saab range from $80 to $600, depending on the specific model and root cause.
Which Saab models have P0300 documented?▼
Au7o has documented P0300 on 2 Saab models: 9-3, 9-5.