Au7o mascotAu7o
Known IssuesTest Hub demo
  1. Au7o
  2. /
  3. Known Issues
  4. /
  5. Volvo
  6. /
  7. 740
Volvo · Known Issues

1991 Volvo 740 Problems: 5 Known Issues

1991 model year · 175+ owner reports · Updated August 2026

Share:@au7o.io

1991 · All trims · All engines

Choose the year and equipment for your written issues and visual request.

No email neededHow interest is saved

Interest applies to the selected vehicle and configuration; it is not a reservation. Voting stores a first-party identifier for up to 180 days to prevent repeat votes. No account or email is needed. Clearing cookies or using another device may count separately. Privacy

Visual coming soon

Your interest helps us choose what to build next.

Visual Known Issues · Coming soon

$4.99/month plus taxes at launch · No payment today

Preview the XT6 example
Known IssuesMotorcycle IssuesDTC LookupDrivePricingAboutTermsPrivacyCookiesConsentData rightsCopyrightFeedback
Share:@au7o.io

Vehicle data and repair guidance on this site are compiled with AI assistance and may contain errors. Always verify with your service manual or a qualified mechanic.

Data protection representation

DataRep representative in the United KingdomDataRep representative in the European Union
Au7o · 2026
Built for DIY mechanics. Privacy-first.
Explore free Hub demo
Issue summary

According to Au7o's analysis of 175+ owner reports, the 1991 Volvo 740 has 5 documented known issues. None of the listed issues is rated critical; this is not a complete reliability assessment. The most commonly reported issue is Overdrive Relay and Solenoid Failure with 175 owner reports. Across all issues with published estimates, repair costs range from $30 to $1,500. DIY maintenance guides at au7o.io.

In This Article

  • 740 Transmission3
  • 740 Cooling1
  • 740 Fuel System1
  • Recalls2
  • FAQ
Get Started
Back to top

In This Article

  • Transmission3
  • Cooling1
  • Fuel System1
  • Recalls2
  • FAQ

All 5 Known Issues

Filter:
ALL YEARS199219911990
Community reported
175 owners

On the 1990-1992 Volvo 740, the AW70/71 automatic transmission in the 740 suffers from overdrive relay and solenoid failures. The overdrive relay on the firewall can corrode, and the M46 overdrive solenoid wears out, causing the transmission to lose its overdrive gear. Without overdrive, the engine revs high on the highway, increasing fuel consumption and wear.

Common Symptoms

  • Overdrive light flashing on dashboard
  • No overdrive engagement on highway
  • Higher than normal RPM at cruising speed
  • Transmission stuck in 3rd gear
  • Clicking from overdrive relay area
  • Poor fuel economy on highway

How to Fix

Replace the overdrive relay (located on the firewall near the brake booster) and test the overdrive solenoid. If the solenoid has failed, it must be replaced, which requires dropping the transmission pan.

Owner tips & cautions

  • TipTest the relay first - it is the most common cause and costs under $30 to replace
Typical repair cost:$50 - $400

Research This Issue

Based on 175 owner reports

GoogleRedditYouTubeNHTSA
Community Reported
High Confidence175 owner reportsLast reported by owners Mar 2026Reviewed Mar 2026

On the 1990-1992 Volvo 740, the AW70/71 automatic transmission overdrive solenoid fails, causing loss of overdrive (4th gear). The transmission also develops governor issues causing erratic shifting.

This issue also affects: Volvo S60, Volvo S70, Volvo XC70

Common Symptoms

  • No overdrive
  • Harsh shifting
  • Transmission not upshifting
  • Flashing OD light

How to Fix

Confirm the fault by checking fuse 11, the shifter-mounted overdrive switch, relay, and 12V power/ground at the AW70/AW71 overdrive solenoid; if the solenoid does not click or has an open/shorted coil, replace the solenoid and pan gasket, then refill with the correct ATF. If overdrive still will not engage or shifts remain erratic, remove and clean/inspect the governor assembly and valve body for sticking weights/valves, worn seals, or debris, and service the transmission filter/screen and fluid at the same time. Typical repair cost is about $150-$350 for an overdrive solenoid replacement with fluid service, while governor/valve body service usually runs $300-$700 depending on labor and parts condition.

What you need to fix it

Only diagnosis- and fitment-reviewed repair parts are linked here.

  • Aftermarket 1239928/1239679 AW70/AW71 overdrive solenoid

    replace an electrically or hydraulically confirmed failed overdrive solenoid Fitment/availability: AW70/AW71 external overdrive-solenoid branch; verify 1990-1992 740 transmission tag and installed part and obtain matching inner and outer…

    IPD USA

As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.

Typical repair cost:$200 - $800

Research This Issue

GoogleRedditYouTubeNHTSA
Community Reported
Medium Confidence

On the 1990-1992 Volvo 740, the AW70/AW71 automatic transmission overdrive unit fails, causing a loss of overdrive gear and sometimes a harsh engagement. The overdrive solenoid and associated wiring are common failure points. Highway RPM increases significantly without overdrive.

This issue also affects: Volvo V70

Common Symptoms

  • No overdrive engagement
  • High RPM on highway
  • Harsh overdrive engagement
  • Overdrive light flashing

How to Fix

Test the overdrive solenoid and wiring first. Replace the solenoid if faulty. If the overdrive clutch pack is worn, a transmission rebuild is needed. The standalone overdrive unit can sometimes be serviced separately.

What you need to fix it

Only diagnosis- and fitment-reviewed repair parts are linked here.

  • Aftermarket 3523804 automatic-overdrive relay

    replace a tested failed overdrive control relay Fitment/availability: White automatic-transmission overdrive-relay branch for applicable 1990-1992 Volvo 740 AW70/AW71/AW72 applications; confirm transmission and installed relay number Fit…

    IPD USA
  • Aftermarket 1239928/1239679 AW70/AW71 overdrive solenoid

    replace a confirmed open, shorted or hydraulically failed external overdrive solenoid Fitment/availability: AW70/AW71 overdrive-solenoid branch; confirm 740 VIN, transmission tag and installed solenoid and obtain the required seals Fitme…

    IPD USA

As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.

Typical repair cost:$100 - $1,500

Research This Issue

GoogleRedditYouTubeNHTSA
Community Reported
Medium Confidence

On the 1990-1992 Volvo 740, the heater core develops a leak, causing a sweet coolant smell inside the cabin, fogging windshield, and wet passenger-side carpet. Replacement requires significant dash disassembly on the 740.

This issue also affects: Volvo S70, Volvo V70

Common Symptoms

  • Sweet smell inside car
  • Fogged windshield
  • Wet passenger carpet
  • Coolant loss
  • Windows fog with defrost on

How to Fix

Replace the heater core. On 740 models this requires removing much of the center console and lower dash. Flush the cooling system and replace coolant. Check heater hoses while accessible.

What you need to fix it

Only diagnosis- and fitment-reviewed repair parts are linked here.

  • Aftermarket 1307236 Volvo 700/900 heater core

    replace a pressure-confirmed leaking heater core Fitment/availability: Volvo 740/700-series heater-core branch including 1990-1992 applications; confirm VIN, HVAC case and installed core dimensions before the labor-intensive teardown Fit…

    IPD USA

As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.

Typical repair cost:$400 - $900

Research This Issue

GoogleRedditYouTubeNHTSA
Community Reported
Medium Confidence

On the 1990-1992 Volvo 740, the Volvo 740 fuel injection relay (commonly called the white relay) is a known failure point. When it fails, the engine cranks but will not start because the fuel pump and fuel injectors lose power.

Common Symptoms

  • Engine cranks but does not start
  • Intermittent no-start condition
  • Engine stalls while driving
  • Fuel pump not priming

How to Fix

What you need to fix it

Only diagnosis- and fitment-reviewed repair parts are linked here.

  • Aftermarket 3523608 white Volvo fuel-system relay

    replace a circuit-tested failed fuel-system relay Fitment/availability: Cataloged for applicable 1990-1992 Volvo 740 LH and Regina branches; confirm the wiring diagram, relay color and installed OE number Fitment/availability: In stock w…

    IPD USA

As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.

Typical repair cost:$30 - $150

Research This Issue

GoogleRedditYouTubeNHTSA
Community Reported
Medium Confidence
NHTSA Recalls2 recalls

SEAT BELTS:FRONT:ANCHORAGE

SAFETY BELTS ARE DESIGNED TO BE ROUTED UNDER A DIAGONAL CROSS BRACE DURING FASTENING. THE INSTRUCTIONAL LABELS FOR THE BELT ROUTING ARE INADEQUATE, AND CAN RESULT IN INADVERTENT RELEASE OF THE BELT BUCKLE.

Campaign #91V07500006/05/1991

FUEL SYSTEM, GASOLINE:STORAGE

FUEL DAMPER LOCATED BEHIND THE FUEL LINE AND THE FUEL RAIL MAY BE IMPROPERLY ASSEMBLED. OVER TIME, THE SOLDER JOINTS COULD ALLOW A SMALL AMOUNT OF FUEL TO LEAK.

Campaign #90V16500006/09/1990

Enter your VIN at NHTSA.gov to check recalls specific to your vehicle.

🔧
A mechanic who knows YOUR exact car
Answers tuned to your year, make, model & trim — not generic advice. Save your garage so it always has the right context.
Get ahead of Volvo 740 problems — free
Leave your email and we'll alert you the moment there's a new recall or known issue for your Volvo 740. Free, no account needed.

Don't see your problem? Describe your symptoms to get a diagnosis, or get a full repair guide.

Other Volvo Models

Volvo S9028Volvo V6028Volvo S6024Volvo XC6019Volvo V7018Volvo XC9017

Frequently Asked Questions

What are the most common Volvo 740 problems?

According to Au7o's analysis of 175+ owner reports, the 1991 Volvo 740 has 5 documented issues. The most frequently reported are: Overdrive Relay and Solenoid Failure, Automatic Transmission Overdrive Solenoid Failure, Heater Core Leak. None are rated critical, but regular maintenance is recommended.

Is the Volvo 740 reliable?

The 1991 Volvo 740 has 5 known issues documented across 175+ owner reports. None of the matching records is rated critical; this is not a complete reliability assessment. Regular maintenance following the manufacturer's schedule helps prevent many common problems.

How much does it cost to fix common Volvo 740 problems?

Repair costs for known Volvo 740 issues range from $30 to $1,500, depending on the specific problem and whether you choose DIY or professional repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.

What is the 1990-1992 Volvo 740 Overdrive Relay and Solenoid Failure?

The AW70/71 automatic transmission in the 740 suffers from overdrive relay and solenoid failures. The overdrive relay on the firewall can corrode, and the M46 overdrive solenoid wears out, causing the transmission to lose its overdrive gear. Without overdrive, the engine revs hig… Repairs typically run $50-$400. Severity: medium.

What is the 1990-1992 Volvo 740 Automatic Transmission Overdrive Solenoid Failure?

The AW70/71 automatic transmission overdrive solenoid fails, causing loss of overdrive (4th gear). The transmission also develops governor issues causing erratic shifting. Repairs typically run $200-$800. Severity: medium.

What is the 1990-1992 Volvo 740 Heater Core Leak?

The heater core develops a leak, causing a sweet coolant smell inside the cabin, fogging windshield, and wet passenger-side carpet. Replacement requires significant dash disassembly on the 740. Repairs typically run $400-$900. Severity: medium.

Content on this page was compiled with AI assistance using NHTSA complaints, TSBs, owner reports, and public automotive data. While we strive for accuracy, this information may contain errors. Always verify repair procedures and specifications with your vehicle's service manual or a qualified mechanic.

Data sourced from 175+ owner reports, NHTSA recalls, TSBs, and automotive forums.

What is the 1990-1992 Volvo 740 Fuel Injection Relay (White Relay) Failure?

The Volvo 740 fuel injection relay (commonly called the white relay) is a known failure point. When it fails, the engine cranks but will not start because the fuel pump and fuel injectors lose power. Repairs typically run $30-$150. Severity: medium.

What is the 1990-1992 Volvo 740 AW70/AW71 Automatic Transmission Overdrive Failure?

The AW70/AW71 automatic transmission overdrive unit fails, causing a loss of overdrive gear and sometimes a harsh engagement. The overdrive solenoid and associated wiring are common failure points. Highway RPM increases significantly without overdrive. Repairs typically run $100-$1,500. Severity: medium.