P1682 on 2009-2016 Chevrolet Traverse: Ignition Circuit Fault Causes and Fixes

What's Unique About the 2009-2016 Chevrolet TRAVERSE

The first-generation Chevrolet Traverse, along with its GM Lambda platform-mates (GMC Acadia, Buick Enclave, and Saturn Outlook), is particularly susceptible to this code due to a well-documented design flaw in the Underhood Fuse Block (UBEC). Multiple GM Technical Service Bulletins (TSBs), including #PIT5643 and #19-NA-276, point specifically to poor terminal tension and subsequent arcing/corrosion at terminal 51 of the X3 connector as the primary cause. This means that while generic causes like a faulty ignition switch are possible, the UBEC is a much more common and vehicle-specific failure point that is often the true culprit.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Engine stalls while driving, sometimes intermittently [7, 9, OWNER COMPLAINT]
• Engine cranks but will not start
• Reduced Engine Power message displayed
• Check Engine Light is on [OWNER COMPLAINT]
• "Service Stabilitrak" or "Traction Control Off" messages displayed
• Engine continues to run after the key is turned off and removed
• Intermittent no-crank, no-start condition
• Weak or dead battery due to modules staying awake

Most Likely Causes

1. Faulty Underhood Fuse Block (UBEC) 🔴 High Probability Multiple GM TSBs (#PIT5643, #19-NA-276) identify poor terminal tension, arcing, and corrosion on terminal 51 of the X3 connector at the UBEC as a primary cause for P1682. Over time, engine vibration and heat cause the connection to loosen, leading to arcing that damages the terminal and the fuse block itself. This is a known defect that has led to class-action lawsuits.
   How to confirm: Disconnect the battery. Remove the UBEC and inspect the large connectors on the bottom. Specifically, examine the gray X3 connector for a small, dark burn mark or discoloration on terminal 51 and its corresponding pin on the fuse block. A magnifying glass or phone camera may be needed to see the subtle arcing spot. The pin may look duller or darker than the surrounding pins.
   Typical fix: Replacement of the entire UBEC assembly is the most common and reliable fix. If the damage is minimal, a skilled technician can replace the single damaged terminal in the harness connector using a terminated lead (pigtail) and replace the fuse block.
   Est. part cost: $300 - $500
2. Faulty Run/Crank or Powertrain Relay 🟡 Medium Probability Relays are electromechanical switches that can fail with age. A faulty relay can fail to provide the second ignition signal to the ECM. A GM document also points to the KR75 Engine Controls Ignition Relay (#70) as a potential cause for a P1682 with a crank/no-start symptom. A loose-fitting relay in its socket can also cause an intermittent connection, mimicking a bad fuse block.
   How to confirm: Swap the run/crank relay (often labeled PWR/TRN) with an identical relay from a non-critical system (like the horn or rear defogger) in the fuse box. If the problem resolves, the relay is bad. This is a common first step for DIY diagnosis due to its low cost and ease.
   Typical fix: Replace the faulty relay. The specific GM part number for the Engine Controls Ignition Relay is cited as 13500118.
   Est. part cost: $10 - $30
3. Faulty Ignition Switch ⚪ Low Probability While ignition switches can fail and cause this code, they are frequently replaced in error for this code on the Traverse and its platform mates. [9, OWNER COMPLAINT] The symptoms of a bad switch are very similar to a bad UBEC, making it a common misdiagnosis. [OWNER COMPLAINT, 18]
   How to confirm: Requires using a multimeter to test for correct voltage output on the different circuits of the ignition switch in each key position. This often requires a wiring diagram and is more involved than inspecting the UBEC.
   Typical fix: Replace the ignition switch.
   Est. part cost: $30 - $80

Rare But Worth Checking

• Wiring Harness Damage: An open or short in the wiring between the ignition switch, UBEC, and ECM can cause this code. TSB #21-NA-032 notes that a compromised dual-crimp connection at pin H6 of the X3 connector can also cause P1682, sometimes accompanied by a P0101 MAF code. This is another failure point within the same connector as the more common pin 51 issue.
• Faulty Engine Control Module (ECM): This is a very rare cause. An owner complaint confirms the ECM was replaced, but the failure recurred, indicating the ECM was not the root cause. [OWNER COMPLAINT] The ECM should only be considered after all other possibilities, especially the UBEC and its wiring, have been exhaustively ruled out.
• Water Intrusion: On some GM trucks, TSB #PIT5546B links P1682 to water intrusion into the headlamp assemblies, which can backfeed voltage into ignition circuits and keep modules awake. While less documented on the Traverse, water leaks from sunroof drains have been anecdotally linked to fuse box corrosion on platform mates. TSB #PIT5643 also advises checking for water intrusion at the IP fuse block.

Diagnosis Steps

1. Scan for all stored trouble codes. Note any other codes, especially P0689, C-codes for Stabilitrak, or P0101.
2. Disconnect the vehicle's battery.
3. Remove the cover from the Underhood Fuse Block (UBEC). Unbolt the main power connections (typically 13mm nuts).
4. Unbolt the four 7mm screws that hold the top half of the fuse block to the bottom half containing the connectors.
5. Carefully unclip and lift the UBEC to access the large electrical connectors on the underside. There are several plastic tabs around the perimeter.
6. Thoroughly inspect the connectors and the UBEC terminals. Specifically, examine the gray X3 connector and the corresponding pin on the fuse block at terminal 51. Look for a small black or brown burn mark, discoloration, or melted plastic. Use a phone camera with zoom to get a clear view.
7. Also inspect terminal H6 on the same X3 connector for a bad wire crimp, as noted in TSB #21-NA-032.
8. If burn marks or damage are found at pin 51, the UBEC must be replaced. The corresponding wire terminal in the connector should also be replaced using a pigtail (GM Part #84757974).
9. If the UBEC appears perfectly clean, the next logical step is to test the run/crank relay by swapping it with a known good relay.
10. If the issue persists, perform electrical tests on the ignition switch circuits to verify correct voltage output before considering replacing the switch.
11. As a final step, check the wiring harness between the ignition switch, UBEC, and ECM for continuity and shorts to ground.

Parts You'll Likely Need

• Underhood Fuse Block (UBEC) (OEM #23106749 (supersedes 22837015, 22837016)) — This is the most common failure point for code P1682 on this platform, due to a known design flaw with internal connections failing at terminal X3-51.
  Trusted brands: ACDelco (Genuine GM), Dorman
  OEM price range: $350-$500
  Aftermarket price range: $300-$400
• UBEC Connector Wire Terminal (OEM #84757974) — If only a single terminal is burned in the connector, a skilled technician can replace just the terminal pigtail instead of the entire harness. This is the official repair recommended by GM TSBs.
  Trusted brands: ACDelco (Genuine GM)
  OEM price range: $20-$40

Related Codes That Often Appear With This One

• P0689 — This code relates to the ECM/PCM Power Relay Control Circuit. Both P0689 and P1682 are mentioned together in TSBs #PIT5643 and #19-NA-276 as being caused by the same fault: poor terminal tension at pin 51 of the UBEC's X3 connector.
• C0242 — This code relates to the Traction Control System. The ECM may disable traction control as a safety measure when a critical powertrain fault like P1682 occurs, leading to the "Service Stabilitrak" message. [7, 17, OWNER COMPLAINT]
• P0101 — This code for Mass Air Flow (MAF) Sensor Performance can appear with P1682. TSB #21-NA-032 warns technicians not to replace the MAF sensor, as the likely cause is a bad wire crimp at terminal H6 of the UBEC X3 connector.

Technical Service Bulletins (TSBs) & Recalls

• PIT5643: Preliminary bulletin identifying arcing/corrosion on terminal 51 of the X3 connector at the UBEC as the cause for DTCs P0689 and/or P1682.
• 19-NA-276: A later, more formal TSB that supersedes the preliminary information, confirming the cause is poor terminal tension on terminal 51 of the X3 connector and providing a repair procedure involving a terminated lead.
• PIT4649D: Diagnostic tip for a Service Engine Soon light with DTC P1682, related to battery draw and no-start conditions.
• 21-NA-032: Warns that P1682 can be set with P0101 due to a bad crimp on terminal H6 of the X3 connector, and to not replace the MAF sensor.

Platform-Specific Known Issues

• TSB #PIT5643 & #19-NA-276: These are the key documents. They instruct technicians to diagnose DTCs P0689 and/or P1682 by inspecting for arcing/corrosion/poor tension on terminal 51 of the X3 connector at the UBEC.
• TSB #21-NA-032: This bulletin warns that P1682 can also be caused by a bad wire crimp at terminal H6 of the same X3 connector, and may be accompanied by a P0101 MAF code. It advises against replacing the MAF sensor.
• Owner Experience: A common owner story involves months of intermittent stalling, multiple trips to the mechanic, and incorrect replacement of the ignition switch, relays, or battery before the UBEC is finally identified as the root cause. [7, OWNER COMPLAINT]

Mechanic-Grade Diagnostic Values

• Scan Tool Voltage Comparison — expected: The 'Ignition 1 Voltage' and 'Engine Controls Ignition Relay Feedback Signal' parameters should have no more than a 3V difference.. Failure: A difference greater than 3V between the two parameters will set the DTC.
• System Voltage at ECM — expected: With ignition ON, the scan tool parameter for the relevant ignition circuit should display between 9-14V.. Failure: A reading less than 9V indicates an open or high resistance in the circuit.
• Circuit Resistance — expected: Less than 6 Ω.. Failure: A resistance of 6 Ω or greater in the circuit or within the underhood fuse block can cause the DTC to set.

Scan Tool Commands That Help

• GDS2/Tech2: Observing 'Ignition 1 Voltage' and 'Engine Controls Ignition Relay Feedback Signal' parameters in the ECM data list. — This is the primary diagnostic step to determine which of the two ignition circuits is dropping out, guiding whether to investigate the Ignition Main Relay circuit or the Engine Controls Ignition Relay circuit.

Wiring & Ground Locations

• X50A Underhood Fuse Block — In the engine compartment, typically on the driver's side.. This is the component officially named in TSBs #19-NA-276 and #PIT5643. The fault occurs at terminal 51 of its X3 connector.
• X3 Connector, Terminal 51 — A specific pin location on one of the large connectors on the underside of the Underhood Fuse Block (X50A).. This is the exact terminal identified by GM as having poor tension, leading to arcing, corrosion, and the P1682/P0689 codes.
• G103 — On the left side of the engine compartment, on the inner fender panel/cowl, often above the brake booster.. This is a major ground point for the Body Control Module (BCM), Instrument Panel Cluster (IPC), and Data Link Connector (DLC). A poor ground here can cause widespread, difficult-to-diagnose electrical issues.
• G110 — On the right rear of the engine, mounted to the back of the cylinder head.. A poor connection at this ground point has been anecdotally linked to intermittent electrical issues after major engine or transmission work, where the bolt was cross-threaded or not tightened properly.

Real Owner Repair Stories

• YouTube user 'Fixing cars and stuff' (2013 Chevrolet Traverse LTZ) — Intermittent P1682 code (about once a month), instrument cluster lights up, 'Traction Control Off' and 'ABS Off' messages, sometimes reduced power, and sometimes complete stalling in the middle of the road.
  ❌ Tried (didn't work) Replacing the ignition and run/crank relays.
  ✅ What actually fixed it Replacing the entire Underhood Fuse Block (UBEC) assembly. The user noted the internal 'stabbing connections' get loose over time, causing the intermittent fault.
• YouTube user 'The Lo-fi Mofo' (2008 Pontiac G6 (Lambda platform relative)) — P1682, intermittent stalling at stoplights, stalling when backing up, eventual no-start. Wiggling a specific relay in the fuse box would allow it to start.
  ❌ Tried (didn't work) Bench testing the original relays (they tested good), replacing the relays with new ones.
  ✅ What actually fixed it The relay socket within the fuse block had become loose, causing a poor connection. The final fix was to replace the entire fuse block assembly.

OEM Part Supersession History

• 22837015, 22837016 → 23106749 — Standard part evolution, likely to address internal component or manufacturing process issues. It is unknown if the X3-51 terminal issue was specifically addressed in the new part.