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1997 Volvo 850 R P0336 Code: Causes, Symptoms & Repair Solutions

Model: 1997 Volvo 850 Fault Code: P0336 Posted: 2007-05-03 15:57

I own a 1997 Volvo 850 R with 82,000 miles. The vehicle begins to shake and stall after driving more than 30 minutes, especially during acceleration from a stop. After checking the onboard diagnostics, I found two trouble codes: P0336 (Crankshaft Position Sensor Circuit Malfunction) and P0172 (Bank 1 Fuel Trim Too Rich). I'm seeking clarification on what these codes mean and how to diagnose and fix them. The symptoms include engine hesitation, loss of power during acceleration—especially on inclines—and the car stalling after warming up. Once it stalls, it won't restart immediately; only after cooling down does it start again. The issue appears to occur consistently after extended driving or repeated stop-start cycles. I recently had the vehicle inspected by a mechanic who suggested that overheating might trigger a 'fail-safe' mode, causing the engine to shut off. However, Volvo service has been unable to reproduce the problem under normal conditions. I have also replaced key components including the radiator, coolant reservoir, alternator, spark plugs, wires, distributor cap, and timing belt. I am new to car maintenance and rely on mechanics for repairs. The vehicle was previously owned by my in-laws who drove it regularly for about 6,000 miles per year before selling it. It sat idle for over a year prior to purchase with no activity. I'm now concerned that the issue may stem from long-term inactivity or component degradation due to age and lack of use. Can anyone confirm what P0336 and P0172 indicate? Are these codes directly linked to the stalling behavior, or could they be secondary symptoms caused by underlying engine problems? What are the most effective diagnostic steps for a 1997 Volvo 850 R owner with limited mechanical experience?

Related fault codes

P0336

Comments (5)

Anonymous 2007-05-03 16:26

P0336 indicates a fault in the crankshaft position sensor or its associated circuit. P0172 means Bank 1 is running too rich—excess fuel in the air-fuel mixture. These issues can cause misfires and contribute to stalling, especially under load. The misfiring may be triggering these codes, or vice versa. Have you reviewed the vehicle’s service history? Has a qualified mechanic performed a full diagnostic check?

Anonymous 2007-05-03 17:53

I purchased this Volvo from my in-laws about a year ago. They drove it for approximately 6,000 miles annually and maintained it regularly until they stopped using it—after which it sat idle for over a year in their driveway. Since then, I’ve invested several thousand dollars into repairs: radiator, coolant reservoir, heater hose, alternator, spark plugs, wires, distributor cap, and timing belt. As a beginner in car repair, I've relied on local mechanics and recently bought the factory repair manual—replacing the radiator myself was surprisingly manageable. The vehicle previously failed smog due to a check engine light not sending a signal—an issue that may relate to sensor failure or wiring problems. Around the time I noticed a radiator leak, I also observed stalling behavior: after the engine warmed up and idling at a stoplight, it would begin to shake and die during acceleration. After stalling, it wouldn’t restart immediately—only after cooling down. Recently, I’ve noticed power loss when accelerating. On flat roads, it takes 1–2 seconds to 'kick in' normally; on inclines, it fails to accelerate at all and jerks forward. I took the car to a mechanic who suggested that overheating triggers a fail-safe shutdown to prevent engine damage. Volvo service has been unable to reproduce this issue under normal driving conditions. The symptoms typically occur after more than 30 minutes of driving or following multiple stop-start cycles.

Anonymous 2007-05-03 18:24

You reported the problem occurring after about 30 minutes of driving—this is a key detail. It may suggest that Volvo service is underestimating the issue, as they often require longer timeframes to reproduce symptoms. While it's possible the vehicle enters fail-safe mode due to overheating, if the condition occurs reliably in your daily commute (e.g., at the end of a half-hour drive or during rush hour), it’s likely not just a software glitch. The ignition module on older Volvo 850 models is known for poor ventilation and heat buildup—this could be contributing to intermittent failures.

Anonymous 2007-05-03 18:36

I can't reproduce the issue 100% of the time, but I’ve observed it reliably about 80% of the time. It typically happens at the end of my workday—after driving for roughly half an hour—or during rush hour when traffic causes frequent stops and starts.

Anonymous 2007-05-04 05:53

Older Volvos, especially models like the 1997 Volvo 850 R, are not ideal for beginners due to complex systems and aging components. If the issue occurs frequently, a dealership should be able to reproduce it under controlled conditions—especially with high-end brands like Volvo that often charge premium labor rates. If I were you, I’d consider repairing the vehicle now before it becomes more costly or difficult to fix. A car that sits idle for long periods is generally less reliable and may not offer good value compared to a frequently driven vehicle, regardless of mileage.