← Back to list

P1689 Diagnostic and Fix for 2001 Dodge 3500 5.9L Diesel - Common Symptoms and Solutions

Model: 2001 dodge 3500 Fault Code: P1689 Posted: 2007-09-19 07:16

A 2001 Dodge 3500 5.9L diesel truck owner reports recurring P1689 trouble code, which indicates a throttle position sensor (TPS) signal issue. The vehicle exhibits symptoms such as inability to exceed 1200 RPM, hesitation during startup, and the check engine light illuminating after cold starts. After multiple attempts including ECM replacement, fuel system checks, and harness modifications, one user found that removing jumpers from the Edge box resolved the issue. Fuel pressure remained stable, and no significant fuel starvation or air intake was observed. The problem appears to be intermittent, with symptoms often returning during cold starts but resolving after engine warm-up. A fuel leak at the pump was identified as a potential contributing factor, though it did not cause immediate fuel starvation. Another user reported success by installing a new ECM and using a spare unit for future use in other vehicles. The P1689 code is linked to TPS signal inconsistencies, possibly due to electrical interference or faulty sensor connections. This case highlights the importance of checking aftermarket electronics (like Bully Dog downladers) and ensuring proper grounding and wiring when diagnosing engine performance issues on 2001 Dodge 3500 diesel models.

Related fault codes

P1689

Comments (13)

Anonymous 2007-09-19 23:58

While driving, the check engine light returned and the truck would not rev past 1200 RPM. After shutting it off and restarting, the issue persisted. Unplugging the ECM temporarily resolved the problem for several days, suggesting a possible electronic module or signal interference.

Anonymous 2007-09-20 08:05

The P1689 code may indicate a misreading of throttle position sensor (TPS) signals sent to the factory PCM. If the TPS is faulty or experiencing electrical noise, it could cause erratic engine behavior. Replacement of the TPS unit—common on this model—is recommended as a diagnostic step.

Anonymous 2007-09-20 08:06

Using a fuel pressure gauge during low-rev conditions can help determine if the issue stems from fuel delivery problems, though in this case, readings were normal. This rules out fuel starvation as the primary cause of hesitation or stalling.

Anonymous 2007-09-25 05:39

The issue occurs only on cold starts and resolves after engine warm-up. The check engine light goes off after a few starts but returns during subsequent cold mornings. I’ve been using the truck as a plow, and it has performed reliably once warmed up.

Anonymous 2007-10-04 05:10

I've updated my situation: I haven’t yet replaced the ECM. Last week, a rear brake line burst between the fuel tank and frame—this is now fixed. The truck has not shown any symptoms since then. I’ve been using a 2001 GMC Sierra HD for the past two weeks due to the diesel issue, which has significantly increased my fuel costs.

Anonymous 2007-10-09 21:25

I discovered a small fuel leak at the fuel pump (mounted under the oil pan). After sitting idle for two weeks, a spot developed beneath it. While this didn’t cause air intake or fuel starvation symptoms, it may have contributed to intermittent engine hesitation during cold starts.

Anonymous 2007-10-10 06:46

A fuel leak at the pump could contribute to inconsistent fuel delivery and potentially trigger P1689 due to sensor misreading from fluctuating pressure or contamination.

Anonymous 2007-12-08 23:43

I replaced the fuel pump seal. The check engine light went out for a few days before returning. This time, the issue occurred when the truck was hot. After removing jumpers from the Edge box (aftermarket ECU), the problem disappeared. I’ve now run it for four days and completed two plowing events with no issues. The P1689 code is gone after key cycling. I now have a spare ECM to use in other vehicles if needed.

Anonymous 2008-01-05 11:38

After over 100 hours of operation, the truck has shown no further symptoms—P1689 is resolved and engine performance remains stable.

Anonymous 2008-01-05 11:51

Congratulations! With all the snow this season, your truck is clearly earning its keep and proving reliable under harsh conditions.

Anonymous 2008-01-05 12:42

This truck has held up well despite typical Dodge rust issues—especially in door bottoms. I power-wash it after every storm to prevent corrosion. I spend more time under the truck than on painted surfaces, and it’s paid off so far. Thanks for the helpful advice; sometimes I’m just too stubborn to see the obvious solutions.

Anonymous 2008-11-01 19:40

I currently have P1693 and P1765 codes as well. These are known issues on my 2000 model, but I'm not sure what exactly triggers them. Any insight would be appreciated—thanks for the help! - Lane

Anonymous 2012-05-29 23:52

I have a 2001 Dodge 3500 with identical symptoms despite replacing the injection pump. I still experience engine hesitation and P1689. I’ve installed a Bully Dog downlader, and unplugging it didn’t fully resolve the issue—this suggests deeper ECU or wiring interference. I’ll remove the device tomorrow to test further. Thanks for pointing this out earlier—I wish I had found this post sooner.