U0073 on 2007-2009 Saturn Vue: Control Module Communication Failure Causes and Fixes

What's Unique About the 2007-2009 Saturn Vue

The 2007-2009 Saturn Vue spans two completely different vehicle generations, which is critical for diagnosing this code. The 2007 model is the last year of the first generation (GM Theta platform), sharing parts with the Chevrolet Equinox and Pontiac Torrent. The 2008-2009 models are the second generation, a rebadged Opel Antara built in Mexico, which later became the Chevrolet Captiva Sport. Because their wiring, module locations, and electronics are entirely different, the specific location of a fault will not be the same. For the 2008-2009 models, a known GM issue involves water leaks from poorly sealed windshields causing corrosion in the X200 harness connector in the driver's side footwell, leading to multiple communication codes including U0073.

Generation note: The 2007 model year is the first generation Vue, built by Saturn in the US on the Theta platform. The 2008-2009 model years are the second generation, which is a rebadged Opel Antara built in Mexico. They share almost no parts, so diagnostic procedures and the location of components like the BCM, EBCM, fuse boxes, and major ground points will be different.

Symptoms You May Notice

• Multiple warning lights on the dashboard (Check Engine, ABS, StabiliTrak, etc.)
• Loss of instrument cluster functions (speedometer, tachometer, or entire display goes blank or shows dashes).
• Transmission may be stuck in one gear (limp mode) or shift harshly.
• Engine may not start, or may stall unexpectedly.
• Loss of power features like power windows, radio, or door locks.
• Driver Information Center (DIC) may display error messages like 'Service StabiliTrak'.
• Unpredictable electrical behavior, such as headlights or AC turning off on their own.

Most Likely Causes

1. Damaged or Corroded Wiring/Connectors 🔴 High Probability On many GM vehicles, wiring harnesses can be susceptible to water intrusion, corrosion, or chafing. For 2008-2009 models, a known weak point is the X200 connector in the driver's footwell, which can get wet from a windshield leak. Other common chafe points are where the engine harness passes through the firewall or contacts the bulkhead.
   How to confirm: A thorough visual inspection of the main wiring harnesses for green/white corrosion, pinched wires, or rodent damage. For 2008-09 models, pull back the driver's side carpet to inspect the large X200 connector for corrosion. A multimeter is needed to check for continuity and shorts between the two CAN bus wires (Pins 6 and 14 at the OBD-II port).
   Typical fix: Repairing the specific section of damaged wire or cleaning/replacing the corroded connector terminals. This is a labor-intensive process.
   Est. part cost: $5-$50 for wire and connectors
2. Poor Ground Connection 🟡 Medium Probability Loose or corroded ground straps are a frequent cause of network issues on GM platforms. A single bad ground can disrupt multiple modules that rely on it as a common reference point. On the 2008+ 3.6L V6, a ground wire near the power steering pump reservoir is known to become brittle and break.
   How to confirm: Locate the main engine, body, and battery ground points. For 2008+ models, key grounds are G201 (behind right front kick panel) and G107 on the engine. Unbolt, clean all contact surfaces to bare metal, and securely retighten.
   Typical fix: Cleaning and securing the ground connection or repairing the broken ground wire.
   Est. part cost: $0-$10
3. Failing Control Module 🟡 Medium Probability An internal failure in any module on the CAN bus (e.g., ECM, TCM, BCM, EBCM) can cause it to broadcast erratically or short out the entire network. The EBCM (ABS module) is particularly susceptible to failure from water intrusion or internal solder joint cracks. 🎬 See how to diagnose and fix the ABS control module.
   How to confirm: This requires a professional scan tool that can show which modules are not communicating. The diagnostic process involves unplugging modules one by one to see if the rest of the network comes back online.
   Typical fix: Replacing the faulty module and performing any necessary programming.
   Est. part cost: $200-$1000+ depending on the module
4. Weak or Failing Battery / Poor Charging System ⚪ Low Probability → Shop Vehicle Battery Low system voltage during startup can prevent modules from initializing correctly, leading to communication faults.
   How to confirm: Test the battery with a multimeter; it should be above 12.4V at rest. With the engine running, the alternator should produce 13.7-14.7V. A load test is the most definitive way to check battery health.
   Typical fix: Replacing the battery or addressing the charging system fault.
   Est. part cost: $150-$250 for a new battery

Rare But Worth Checking

• Faulty Aftermarket Electronics: A poorly installed remote starter, alarm, or stereo can interfere with the CAN bus wiring, causing network errors. These devices are often improperly spliced into the network and should be disconnected as a first diagnostic step.

Diagnosis Steps

1. Check Battery and Charging System: Ensure the battery is fully charged and terminals are clean. Verify proper alternator output (13.7-14.7V). A weak power supply is a common cause of network issues.
2. Perform a Full Vehicle DTC Scan: Use a high-quality scan tool to pull codes from ALL modules. Note which modules are reporting 'Lost Communication' and which are not responding at all. This helps narrow down the search.
3. Visual Inspection (Key Areas): Thoroughly inspect all visible wiring harnesses. For 2008-2009 models, pull up the driver's side floor covering and inspect the large X200 connector for any signs of moisture or green/blue corrosion. Also check the engine harness where it passes near the bulkhead.
4. Check Grounds: Locate, remove, clean, and tighten the main battery, engine, and chassis ground connections. On 2008+ models, pay special attention to grounds G101, G107, and G201.
5. Check CAN Bus Terminating Resistors: The CAN bus has two 120-ohm resistors. With the battery disconnected, measure the resistance between Pin 6 (CAN-High) and Pin 14 (CAN-Low) at the OBD-II port. A healthy network should read approximately 60 ohms. A reading of 120 ohms indicates an open circuit or a missing resistor/module. A reading near 0 ohms indicates a short between the two wires.
6. Isolate Modules (Professional Step): If the network is down (reading 0 or 120 ohms), begin unplugging non-essential modules one at a time (e.g., radio, HVAC) to see if the network resistance returns to 60 ohms. If it does, the last module unplugged is likely the cause. If not, proceed to essential modules like the EBCM, BCM, TCM, and finally the ECM.
🎬 Watch a real-world case study on fixing no-communication issues.
7. Test CAN Wiring (Professional Step): If a module is not the cause, use an oscilloscope to check the CAN bus signal for a clean waveform. This can identify electrical interference or shorts that a multimeter would miss.

Parts You'll Likely Need

• Wiring Harness Repair Supplies — If the cause is a corroded or broken wire, repairing the harness is the fix. This is more common than module failure.
  OEM price range: $10-$50
  Aftermarket price range: $5-$25
• Body Control Module (BCM) (OEM #2007: 15807076, 22732608; 2008-2009: 25910474, 22860591) — The BCM acts as a central gateway for many network communications. If it fails, it can bring down the entire network. This should only be replaced after exhaustive diagnosis proves it is the fault.
  Trusted brands: ACDelco
  OEM price range: $300-$500
  Aftermarket price range: $200-$400
• Electronic Brake Control Module (EBCM) (OEM #2007: 19416880 (FWD), 15776482 (AWD); 2008-2009: 19153229, 25913856) — The ABS module is another common point of failure that can short the CAN bus. Water intrusion is a common failure mode for these modules.
  Trusted brands: ACDelco, Bosch
  OEM price range: $250-$450
  Aftermarket price range: $200-$350

Related Codes That Often Appear With This One

• U0100 — Lost Communication with ECM/PCM
• U0101 — Lost Communication with TCM
• U0121 — Lost Communication with Anti-Lock Brake System (ABS) Control Module
• U0140 — Lost Communication with Body Control Module (BCM)

Technical Service Bulletins (TSBs) & Recalls

• GM TSB #PIT4730: Discusses intermittent issues like door locks cycling, no-start, and DIC messages with U0140 or U0073 stored as history codes, often related to intermittent wiring faults.
• GM TSB #19-NA-113: Points to the engine harness chafing against the bulkhead as a cause for various communication DTCs including U0073, U0100, U0101, and U0121.
• Unofficial GM PI (Preliminary Information): Mentions water leaks from the windshield causing corrosion in the X200 connector in the driver's footwell, leading to multiple communication codes including U0073.

Mechanic-Grade Diagnostic Values

• High-Speed GMLAN Bus Resistance — expected: 60 ohms (+/- 5 ohms) between DLC pins 6 and 14 with battery disconnected.. Failure: A reading of 120 ohms indicates an open circuit or one of the two terminating resistors is offline. A reading near 0 ohms indicates the GMLAN High and Low wires are shorted together. A reading higher than 65 ohms can indicate high resistance in a connection.
• High-Speed GMLAN Bus Voltage (Key On, Engine Off) — expected: GMLAN-High (Pin 6) should average 2.66V. GMLAN-Low (Pin 14) should average 2.34V. Both wires will show a base of 2.5V and toggle.. Failure: When a '0' is transmitted, GMLAN-High is driven to ~3.5V and GMLAN-Low is driven to ~1.5V. Incorrect voltages or a lack of toggling indicates a short to power/ground or a faulty module driver.
• Battery Voltage — expected: Above 12.4V at rest. 13.7V to 14.7V with engine running.. Failure: Low voltage during startup can prevent modules from initializing correctly, causing communication codes.

Scan Tool Commands That Help

• Tech2 / GDS2 with SPS (Service Programming System): BCM Programming / RPO Configuration — This is required any time the Body Control Module (BCM) is replaced. The new module must be programmed with the vehicle's specific VIN and RPO (Regular Production Option) codes to ensure all features work correctly.
• Tech2 / GDS2 with SPS (Service Programming System): EBCM Programming and Setup — Required when the Electronic Brake Control Module (EBCM) is replaced. After programming, additional setup procedures like 'EBCM Relearn' and 'Acceleration Sensor Reset' may be necessary. A new EBCM will set a C0569 code until it is programmed.
• Auto101 GM Tool App (with J2534 interface): Setup SDM — After replacing a BCM and performing the key relearn, a B1001 code may appear, indicating the Supplemental Inflatable Restraint Module (SDM) needs to be set up with the new BCM. This function performs that setup.

Wiring & Ground Locations

• G107 (3.6L V6) — On the 2008-2009 3.6L V6, located at the rear of the engine.. This is a primary engine ground. A poor connection here can cause widespread communication and sensor issues.
• G201 (2008-2009) — Located behind the right front kick panel in the passenger footwell.. This is a major interior body ground. Many modules inside the cabin, including potentially the BCM or other network modules, rely on this ground point.
• G203 (2008-2009) — Located near the lower center of the dash, on the instrument panel (I/P) fuse block.. Provides a ground reference for the I/P fuse block and multiple components connected to it, which can include network modules.
• Ignition Coil Ground (3.6L V6) — For the rear bank of cylinders (1, 3, 5), the ground wire routes from the coils, along the front valve cover, and terminates on a stud near the power steering pump reservoir.. This specific ground wire is known to become brittle and break from heat and age. While it primarily causes misfires, the resulting electrical noise and open circuit can potentially interfere with network communications.
• X200 Connector (2008-2009) — A large, multi-pin harness connector located in the driver's side footwell, under the carpet/kick panel area.. This is a major harness junction. It is a known weak point for water intrusion from windshield or sunroof leaks, leading to corrosion on the GMLAN pins and causing a U0073 code.

Real Owner Repair Stories

• Reddit user in r/Saturn_Cars (2008 Saturn Vue with 3.6L V6) — Misfires on cylinders 1, 3, 5 and an open circuit code on a scan tool.
  ❌ Tried (didn't work) Initial checks focused on fusible links.
  ✅ What actually fixed it The ground wire for the rear bank of ignition coils (cylinders 1,3,5) had become brittle with age and broken. The wire was found to terminate near the power steering pump reservoir. Repairing the broken ground wire resolved the issue.
• Saturn Forum user (2007 Saturn Vue) — BCM failure, car at dealer for over a month.
  ❌ Tried (didn't work) The GM dealer tried to program two different replacement BCMs., Neither module would accept the programming download from GM's system.
  ✅ What actually fixed it The story was unresolved, but highlights a significant real-world problem: programming failures. The technician suspected the issue was with the software download from GM, not the vehicle or the new parts, leaving the car inoperable. This indicates a potential risk even when following correct procedures.

OEM Part Supersession History

• 25910474 → 22860591, 84922494 (and others) — Part revision and consolidation by GM.
  Heads up: Part number 25910474 for the 2008-2009 Vue BCM is part of a large family of interchangeable modules used across many GM vehicles from 2006-2013. Many part numbers, including 15921352, 20864767, 20935349, and 22860591, can be used as replacements as long as they are programmed correctly for the Vue.
• 19153229 → N/A — N/A
  Heads up: This EBCM part number for the 2008 Vue is also listed for the 2008 Pontiac Torrent and Chevrolet Equinox, but NOT the 2007 models, highlighting the platform change. It requires programming after installation.

Model Year Variations Within This Range

• 2007 vs 2008-2009: The entire vehicle platform. The 2007 model is a first-generation Saturn Vue on the GM Theta platform. The 2008-2009 models are second-generation, based on the Opel Antara. Wiring diagrams, module locations, ground points, and part numbers (like for the BCM and EBCM) are completely different and not interchangeable between these generations.

Diagnostic Flowchart

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: A used BCM or EBCM from a junkyard can be a cost-effective option, but ONLY if you have access to the proper programming tools or a service that can program it for you. For the first-generation (2007), some owners have had success with a 'key relearn' procedure, but this is less reliable for the second generation (2008-2009).

Donor-vehicle mileage cap: roughly under 150000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• Check for a matching part number, although many BCMs are interchangeable if programmed.
• Inspect the module's connectors for any signs of corrosion, bent pins, or water damage. Do not buy if there is any visible damage.
• If possible, choose a donor vehicle that was not involved in a front-end collision or flood.
• Ask the dismantler about the vehicle's history if available (e.g., running when parked).

OEM-only on this vehicle (don't cheap out):

• Body Control Module (BCM)
• Electronic Brake Control Module (EBCM)

Aftermarket brands forum-validated for this vehicle:

• For remanufactured modules, companies that offer pre-programming to your VIN are a good option (e.g., services found on eBay, dedicated ECU/BCM repair shops).

Brands owners have reported issues with on this vehicle:

• Avoid unbranded, 'as-is' used modules from private sellers unless you can verify the part number and have a confirmed method for programming, as they can be VIN-locked and unusable.

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• U0100 — Lost Communication With ECM. This code is frequently caused by the same root issues as U0073, such as engine harness chafing against the bulkhead, as noted in TSB #19-NA-113.
• U0101 — Lost Communication with TCM. Often appears with U0073 when a network-wide wiring issue or a bad ground disrupts communication to multiple critical modules like the Transmission Control Module.
• U0121 — Lost Communication With ABS Control Module. Can be set when the EBCM (ABS module) itself fails or when a wiring fault prevents it from communicating, which also brings down the entire network and triggers U0073.
• U0140 — Lost Communication With Body Control Module. TSB #PIT4730 notes that U0140 and U0073 are often stored together as history codes, pointing towards an intermittent wiring fault as the underlying cause.
• P0700 — Transmission Control System (MIL Request). This is a companion code set by the TCM when it can no longer communicate with the ECM or other modules due to a network fault that also causes U0073.

Frequently Asked Questions