Toyota Error Code P3191 – Engine Does Not Start

Error Code: P3191 Affected Component: Engine Does Not Start System: Engine / Fuel / Ignition / Air Intake Severity: Moderate to High – May result in complete failure to start

🔍 What Does Toyota Error Code P3191 Mean?

P3191 – Engine Does Not Start indicates that the Engine Control Module (ECM) has attempted to start the engine but failed after a designated number of cranking attempts. This code typically means there is a failure in air, fuel, or ignition delivery.

📍 When and Why It Appears

• The engine cranks but doesn’t start
• The car stalls immediately after starting
• Occurs after prolonged parking, battery replacement, or cold weather
• Failure in air/fuel/spark during the starting phase

⚠️ Common Symptoms of P3191

• Engine cranks but fails to start
• Rough idle or engine stalling immediately
• Check Engine Light (CEL) illuminated
• Reduced fuel efficiency or intermittent misfires

🔎 Possible Causes

• Dirty or failed Mass Air Flow (MAF) sensor
• Weak fuel pump or clogged fuel filter
• Old, fouled, or worn spark plugs
• Low battery voltage or weak battery during crank
• Vacuum leaks or air intake system faults
• Dirty throttle body or stuck idle air control valve
• Faulty crankshaft or camshaft position sensor

🧰 How to Diagnose Toyota Code P3191

1. Use an OBD-II scanner to confirm P3191 and check freeze frame data
2. Inspect battery voltage during ignition (should be >12.4V resting)
3. Test fuel pump pressure and injector pulse
4. Check spark plug condition and ignition coil function
5. Clean MAF sensor and throttle body using appropriate cleaner
6. Check for additional DTCs like P1604, P0171, or P030x series (misfires)

🔧 How to Fix Toyota Error Code P3191

1. Clean or replace the MAF sensor
2. Replace spark plugs and coils if they are aged or fouled
3. Replace fuel pump or fuel filter if pressure is low
4. Charge or replace battery if voltage drops significantly during crank
5. Fix any vacuum leaks in the intake system
6. Perform idle relearn after throttle body cleaning (if needed)
7. Clear codes and verify fix with multiple successful engine starts

💰 Estimated Repair Costs

• Battery Replacement: ₱3,000 – ₱6,000
• Fuel Pump: ₱4,000 – ₱8,000
• MAF Sensor Cleaning: ₱300 – ₱800 / Replacement: ₱2,000 – ₱5,000
• Spark Plugs: ₱800 – ₱2,000
• Throttle Body Cleaning: ₱500 – ₱1,200
• Labor: ₱1,000 – ₱2,000

🧠 Expert Tips

• This code often appears with P1604 – always fix air/fuel/spark delivery first
• Always scan for multiple codes; P3191 rarely appears alone
• Cold weather and low fuel pressure amplify P3191 occurrences

❓ FAQ – Toyota P3191

Is this code serious?

Yes, it can prevent the engine from starting entirely. Prompt diagnosis is needed.

Does this mean my starter is bad?

Not likely. This code points more to a fuel, air, or spark issue during startup—not the starter motor itself.

Will replacing the battery fix it?

Only if the root cause is low cranking voltage. Run full diagnostics first.

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