Toyota P1604 Code: Startability Malfunction
Toyota's ECM recorded a start that took too long, failed, or died within seconds of firing.
At a glance
Severity: Moderate
- Meaning
- Startability Malfunction
- System
- Fuel & Air Metering · Powertrain
- Safe to drive?
- With caution
- Typical repair cost
- $90–$1,100
- DIY difficulty
- Moderate
P1604 is Toyota's hard-start record, used on Camry, Corolla, RAV4, Tundra and many other models from roughly the mid-2000s on. The ECM stores it in one trip when either the engine stays below about 500 rpm for too long while the starter signal is active, or the engine fires past 500 rpm and then falls back to 200 rpm or less within about two seconds. Two freeze frame flags show which happened: Engine Start Hesitation for a long crank, Low Rev for Eng Start for a catch-and-die start. The recorded cranking speed narrows it down further: 0 rpm means the engine never turned, roughly 60 to 250 rpm means it cranked without firing, and higher values mean it fired late. As with its sibling codes, Toyota says to check for an empty tank first, because running out of fuel also sets it.
Can I keep driving? If the car starts and runs normally once going, it's drivable, but a worsening hard start can leave you stranded. Get the battery and fuel system checked before the next cold spell or long trip.
How to read P1604
- P Powertrain
- 1 Manufacturer-specific
- 6 Computer & outputs
- 04 Specific fault
Symptoms
- Long cranking before the engine catches, especially after sitting for hours
- Engine starts, runs for a second and dies, then starts on the second try
- Hard start only right after refueling
- Slow, labored cranking on cold mornings
- Code found on a scan even though the check engine light was off
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Weak battery, corroded terminals or a tired starter giving slow cranking
- Fuel pressure bleeding off overnight through a leaking pump check valve or injector
- Purge VSV stuck open, loading the intake with vapor after refueling
- Ran out of fuel or very low fuel level
- Coolant temperature sensor reading wrong, so cold-start enrichment is off
- Weak fuel pump, worn spark plugs or ignition coils
- Crank or cam sensor signal dropouts, or ECM calibration issue
Diagnosis step by step
Decode the freeze frame
Check which flag is on, Engine Start Hesitation or Low Rev for Eng Start, and the engine speed recorded. Zero rpm points to the battery, starter or a seized engine; about 60 to 250 rpm with no firing points to fuel or spark; a catch-and-die start points to air leaks, throttle deposits, purge or VVT.
Tools: OBD-II scanner
Test battery and cranking voltage
A healthy battery rests around 12.6 V and should not dip much below 9.5 to 10 V while cranking. Lower readings, or a big voltage drop across the cables and terminals, explain slow cranking before anything else is suspected.
Tools: Multimeter
Check fuel pressure and hold
Connect a gauge, run the pump and note pressure (many port-injected Toyotas specify roughly 44 to 50 psi), then shut off and watch it for five minutes. It should stay above about 21 psi; a fast drop means a leaking pump check valve, regulator or injector.
Tools: Fuel pressure gauge
Rule out the purge valve
If starts are only bad after filling up, pinch the purge line or test the purge VSV for leakage with the engine off. A valve that doesn't seal lets vapor from the canister flood the intake during cranking.
Tools: Pliers
Compare coolant and intake temperatures
After the car has sat overnight, coolant and intake air temperature on the scan tool should read within a few degrees of each other and of outside air. A coolant sensor reading warm on a cold engine starves the start of fuel.
Tools: OBD-II scanner
Check for software updates
For some models Toyota has released ECM calibration updates for extended cranking. A dealer can check by VIN whether one applies before parts are replaced.
Tools: OBD-II scanner
Where the parts are
- 1Ignition coil
- 2Spark plug
- 3Fuel injector
- 4Camshaft sensor
- 5Crankshaft sensor
- 6Engine computer (ECM)
- 7Intake manifold
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Replace battery / clean terminals | Yes | $150–$320 |
| Replace starter motor | No | $350–$800 |
| Replace fuel pump assembly (check valve leak) | No | $450–$1,100 |
| Replace purge VSV | Yes | $120–$300 |
| Replace coolant temperature sensor | Yes | $90–$220 |
Rough US estimates for parts and labor; shop rates vary by region. Not a quote.
Notes by brand
Toyota
On flex-fuel 5.7-liter Tundra and Sequoia (3UR-FBE), Toyota issued a service bulletin for extended cranking with P1604 and fuel-trim codes, fixed with an ECM software update. Ask a dealer to check by VIN.
Emissions / smog test impact
Depends
P1604 is a history code that is often stored without the check engine light; an OBD smog check depends on whether the light is on and the monitors are ready. Fix the cause, but avoid clearing codes right before the test.
Frequently asked questions
Why does my Toyota only start hard after I fill up?
That points to the EVAP purge valve. If it doesn't seal, fuel vapor pushed into the canister during refueling flows into the intake while cranking and floods the engine.
The car starts fine now. Can I ignore P1604?
If it was a one-off after running out of fuel, yes, just clear it. If long cranks keep happening, the stored freeze frames are the best clue you'll get, so have them read before clearing.
What do Engine Start Hesitation and Low Rev for Eng Start mean?
They are Toyota freeze frame flags. The first means the engine didn't reach its starting speed in time, the second that it started and then died within about two seconds.
Can a weak battery set P1604?
Yes. Slow cranking keeps engine speed under the threshold for too long, which is exactly what the ECM measures. It's the cheapest thing to test first.
Sources
- Manufacturer public service information (cross-checked)
- NHTSA Complaints API
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