P0795 and P0708 OBD2 Codes on 2001 Saturn SL2: Transmission Range Sensor Fault Diagnosis and Fix

The most likely causes are either a wiring issue connecting the transmission range sensor or a faulty sensor itself. A shifter adjustment problem is possible but less common. I'm not certain whether the sensor is located internally in the valve body or externally on the top/side of the transmission. Could you clarify what the original transmission failure was? Was the valve body replaced during the rebuild, or was it simply a full transmission swap?

The initial issue was erratic overdrive shifting. The used car dealer replaced the entire transmission, which initially fixed that problem—but introduced a new fault shortly afterward. Upon investigation, I discovered that the mechanic failed to connect the black/white wire, which provides essential ground for the transmission range sensor. This wire is often confused because there are two closely spaced 1/4-inch spade terminals: one for testing and one for grounding. The test terminal has a small tab to prevent accidental connection. A common misconception—especially on platforms like AllData (AutoZone)—is that the transaxle case provides ground. In reality, the transmission will not shift smoothly without this black/white wire connected. Even if the sensor is removed or faulty, the transmission can operate—but it will behave poorly: gear shifts are abrupt and harsh, especially when moving between reverse and drive. When the PCM detects a fault in the range sensor, the vehicle defaults to second gear upon startup—a clear indicator of potential sensor issues. To properly adjust the sensor, one must first identify the correct pins on the PCM connector (available via AllData or manufacturer documentation). Without this, it's nearly impossible to verify which pin is active with a multimeter. The PCM connector is located directly on top of the transmission and is easily visible for inspection.

It’s surprising that the fault code didn’t appear sooner if the ground wire was left disconnected. The PCM should detect such a failure much earlier, especially within early miles after installation. I’m glad it's now resolved—hope no internal transmission damage occurred. Cheers, Jeff

Hi Jeff—just wanted to share long-term progress on this issue. The P0795 code reappeared once after the fix, but only as a pending (non-active) code. My scanner is an Actron 9135. I noticed it during a routine check of the secondary air injection system last week. The great news? The transmission has been performing flawlessly ever since! I’ve never driven a Saturn SL2 before, but after this fix, I can’t believe how smooth and precise the shifts are. It’s like driving a snowmobile—no mushiness or hesitation. The 1.9L engine is surprisingly quick, matching the performance of my V6 Tacoma pickup, and it achieves nearly 40 mpg even with A/C on and cruising at 75 mph. Thanks for your detailed guidance—it made all the difference! Gary B

I recall that some modern transmissions—like Chrysler’s CVT or Nissan’s experimental units—use similar shift logic. However, I’m not sure if Saturn models used anything comparable in this era.

I recently replaced the transmission range sensor on my son's 1998 Saturn SL2 and found it surprisingly straightforward once I understood how to adjust it. The black/white wire is absolutely critical—there’s no internal ground connection in the transaxle case. Without this wire, the transmission will not shift smoothly. The adjustment process involves a unique male spade connector (the 'adjust tab') that connects precisely to the ground terminal (a second male spade) located at the center of the 'D' gear range. Here’s how I did it: 1. Shift the vehicle into 'D'. 2. Use a test light, continuity tester, or multimeter across both terminals—the adjust tab and the ground terminal. 3. Loosen the two retaining bolts and slowly rotate the sensor in both directions until continuity is detected (test light illuminates, ohms read near 0, or continuity tester beeps). 4. While maintaining continuity, tighten the bolts securely. 5. Remove the test device and reconnect the black/white wire. This procedure ensures proper sensor alignment and grounding. Dave

Dave, you're absolutely right! I finally understand what that second tab is for—thanks for clarifying!

Dave, thank you for sharing this detailed procedure—it’s the only one I’ve found online. Since I’m not currently at the vehicle, I can’t verify the exact location of the terminals you described. As I recall, there is a multi-wire connector on the side of the sensor (likely handling circuits 771, 772, 773, and 776), while a single terminal on top appears to be grounded. I assume that’s the ground connection you're referring to. Could you confirm where exactly the test terminal is located? Is it the second connector beside the ground one—on my sensor, it looks like it was snipped off so the blade can’t accidentally connect there—or is it somewhere else? By the way, the vehicle I’m working on is a 1996 Saturn SL2—not a 1998—but based on what I’ve found, the transmission range sensor behavior and adjustment procedures appear consistent across these models. Thanks for your help. Saturn doesn’t seem to want to provide clear instructions—they just charge you to fix it! Rick