P1660 on Acura: How to Diagnose & Fix
P1660 — Acura-specific definition
1 Acura model · 1 documented issue · $150-$3,500 repair
P1660 on Acura by model: symptoms, diagnosis and fix
The Honda MP7A/SP7A/S4XA 4-speed automatic in the Integra is notoriously sensitive to fluid condition and shift-solenoid contamination. Solenoid A/B failure causes flashing D4 light, harsh or missed 2-3/3-4 shifts, loss of power in D4/D3, and sometimes speedometer drop-out. Shifting problems can also stem from a clogged transmission filter or screen restricting fluid flow, which lowers hydraulic pressure and leads to missed 4th-gear shifts and failure to downshift. In one owner report, the car suddenly lost almost all power in D4, would not shift, and the speedometer stopped working; the codes returned were Automatic Transaxle FI A circuit failure and ELD error.
Common Symptoms
- flashing D4 indicator
- harsh 2-3 shift
- no 4th gear
- loss of power in D4/D3
- speedometer intermittent
- shift hold in gear
How to Fix
Drain-and-fill with Honda ATF-Z1/DW-1 (never use generic Dexron — it will destroy the clutches). Change the fluid every 3 years/36,000 miles; it breaks down with heat and wear just like engine oil. Pull codes with a Honda jumper or scan tool; the lock-up and shift solenoids are external, three-bolt parts accessible from the engine bay and often just need cleaning. A failed lock-up solenoid sets a general Code 70 (Automatic Transaxle) check-engine light; the solenoid costs less than $200 to replace.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Honda 08200-9008 ATF DW-1 (ATF-Z1), 2 quarts
Repair fluid Honda/Acura automatics requiring ATF-Z1 or DW-1; the issue is specifically the Integra four-speed automatic.
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Owner tips & cautions
- WarningUse only Honda ATF-Z1 or DW-1. Generic ATF causes shift flare and premature failure.
- TipPull the specific solenoid code before condemning the transmission — a $150 solenoid often fixes it.
Sources for this issue (2)
P1660 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P1660 mean on a Acura?
On Acura, P1660: Honda/Acura define P1660 as "A/T-FI Data Line Failure/TCM - ECM Halt" (signal line between the transmission and engine control modules) - https://ericthecarguy.com/hondaacura-p1600-to-p1895-obd-ii On Acura it is documented across 1 model: Integra.
How much does it cost to fix P1660 on a Acura?
Published repair estimates on Acura range from $150 to $3,500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.