P1604 on Toyota
Startability malfunction (Toyota and Subaru)
Severity: Inspect soon
On Toyota and Subaru, P1604 means the engine was slow to start or nearly stalled right after starting. The car usually still runs, but the cause (often a weak battery) can leave you unable to start it. Get it checked soon.
It gets more serious if:
- Stop: The engine stalls or loses power while driving. Subaru owners report P1604 stored with a shorted ignition coil, a blown fuse and a stall at road speed. Get off the road safely and have it checked or towed before driving again.
This page covers only what differs on Toyota. For what P1604 means, the ranked causes and the test order, see the P1604 guide.
What's different on Toyota
ToyotaYour car
2009–2018 · Sequoia · 3UR-FBE
Supported by vehicle dataOn the flex-fuel 3UR-FBE, Toyota links P1604 and hard starting to a wrong alcohol estimate (T-SB-0166-19).
2009–2019 · Tundra · 3UR-FBE
Supported by vehicle dataOn the flex-fuel 3UR-FBE, Toyota links P1604 and hard starting to a wrong alcohol estimate (T-SB-0166-19).
2014–2018 · Highlander
Supported by vehicle dataCheck the ECM connector for corrosion if an aftermarket windshield de-icer is fitted (T-SB-0072-19).
T-SB-0166-19Status unverified
Toyota T-SB-0166-19: 3UR-FBE hard start, MIL with P1604 and fuel trim codes
2009–2019sequoia, tundra · 3UR-FBE · issued · NHTSA 10171454
Hard start or MIL with P1604 or fuel trim codes, with an alcohol density estimate higher than the fuel used. Covers 2009-2018 Sequoia and 2009-2019 Tundra; supersedes T-SB-0058-13, which reprogrammed the ECM.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
T-SB-0072-19Status unverified
Toyota T-SB-0072-19: drivability and P1604 from ECM connector corrosion
2014–2018highlander · issued · NHTSA 10162756
Corrosion in the ECM connector from aftermarket windshield de-icer harnesses can cause drivability problems, low fuel pressure and codes including P1604.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
Sources and review
- Toyota T-SB-0166-19 Rev1: 3UR-FBE hard start, MIL with P1604 and fuel trim DTCs
- ALLDATA Tech Tip: Sequoia extended cranking, DTCs P1601-P1605
- Toyota T-SB-0072-19: 2014-2018 Highlander drivability, P1603/P1604/P1605, connector corrosion
- Foreign Service, July 2013: Toyota P1604 startability code
- Subaru 11-192-19: ECM reprogramming for extended cranking and P1604
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error