P0700 on 2007-2009 Saturn Aura: Transmission Control System Fault Causes and Fixes

What's Unique About the 2007-2009 Saturn Aura

The 2007-2009 Saturn Aura was equipped with either a 4-speed (4T45-E) or a 6-speed (6T70/6T75) automatic transmission. The 6-speed models are particularly known for two major, well-documented issues. First is a high-failure-rate internal component called the 3-5-R wave plate. A fracture of this plate leads to the loss of 3rd, 5th, and Reverse gears and will set a P0700 code along with other specific DTCs. Second, failure of the Transmission Electro-Hydraulic Control Module (TEHCM) itself, which integrates the TCM, valve body, and solenoids into a single unit inside the transmission housing, is a widely reported issue. Its location exposes it to heat and vibration, contributing to electronic failures.

Symptoms You May Notice

• Check Engine Light is on
• Harsh, erratic, or delayed shifting
• A noticeable 'flare' or RPM surge between shifts, especially the 2-3 or 4-5 shift
• Vehicle gets stuck in one gear (limp mode)
• Complete loss of Reverse, 3rd, or 5th gears
• Delayed engagement when shifting from Park to Drive or Reverse, sometimes taking several seconds
• Flashing or incorrect gear position indicator (PRNDL)
• Reduced fuel economy
• Unusual clunking or grinding noises from the transmission area

Most Likely Causes

1. Other Transmission-Specific DTCs Stored 🔴 High Probability → Shop Transmission Assembly P0700 is an informational code by design, triggered by other faults. It is a request from the TCM to the ECM to turn on the check engine light.
   How to confirm: Use an advanced scan tool capable of communicating with the Transmission Control Module (TCM) to read the specific fault codes. A basic OBD-II reader will only show the P0700 from the ECM.
   Typical fix: Diagnose and repair the root cause indicated by the specific transmission codes found in the TCM (e.g., P0776, U0101).
   Est. part cost: $0
2. Broken 3-5-R Wave Plate (6-Speed 6T70/6T75 Transmission) 🔴 High Probability This is a well-documented, common failure on this GM transmission due to a design flaw in the original wave plate. GM issued a special coverage program (14404B) extending the warranty for this specific failure to 10 years or 120,000 miles. An updated, more robust wave plate was later released.
   How to confirm: Confirm the vehicle has a 6-speed transmission. Symptoms are a sudden loss of 3rd, 5th, and Reverse gears. Specific codes like P0776 (Clutch Pressure Control Solenoid 2 Stuck Off) often accompany this failure. Final diagnosis requires transmission disassembly to visually inspect the broken pieces of the wave plate.
   Typical fix: The transmission must be removed and disassembled to replace the broken wave plate (with updated part 24254103) and any related damaged components. The entire transmission must be cleaned of metal debris. This is a major repair often requiring a full rebuild.
   Est. part cost: $50-$150 for a wave plate and seal kit, but often part of a larger $400-$800 rebuild kit. Labor is the primary cost.
3. Failed Transmission Control Module (TCM/TEHCM) 🟡 Medium Probability → Shop Transmission Assembly The TCM is integrated into the TEHCM (Transmission Electro-Hydraulic Control Module) and located inside the transmission's side cover, where it is exposed to constant heat and vibration, leading to a higher rate of electronic failure.
   How to confirm: Look for codes like U0101 (Lost Communication with TCM) or other U-codes alongside P0700. If a capable scan tool cannot communicate with the TCM at all, it points to a failed module or a wiring/power issue. The TEHCM can also fail internally, causing specific solenoid performance codes.
   Typical fix: The transmission side cover is removed to access and replace the TEHCM. The new module (e.g., ACDelco P/N 24256861) must be programmed 🎬 Watch: How to replace the TCM in your Saturn Aura to the vehicle's VIN using specialized dealer or pass-through equipment.
   Est. part cost: $300-$600 for the TEHCM part itself.
4. Failed Shift Solenoid or Valve Body 🟡 Medium Probability → Shop Transmission Valve Body
   How to confirm: Scan the TCM for solenoid-specific codes (e.g., P0750-P079x series). For the 6T70 transmission, the solenoids are part of the TEHCM assembly and are not serviced separately. Therefore, a solenoid code typically points to a TEHCM failure.
   Typical fix: For the 6-speed 6T70, the entire TEHCM assembly is replaced. For the 4-speed 4T45-E, individual solenoids may be replaceable by removing the transmission oil pan and/or side cover.
   Est. part cost: $50-$150 (for individual 4-speed solenoids), $300-$600 (for 6-speed TEHCM assembly).
5. Low or Degraded Transmission Fluid ⚪ Low Probability → Shop Transmission Assembly
   How to confirm: Check the transmission fluid level and condition. The fluid should be bright red and not smell burnt. Dark, burnt-smelling fluid or fluid with metallic particles indicates a more severe internal problem, often related to wave plate or clutch failure.
   Typical fix: Top off the fluid if low. If the fluid is old or dirty, perform a fluid and filter change using the correct fluid type (ACDelco DEXRON-VI). A fluid change will not fix a mechanical failure like a broken wave plate.
   Est. part cost: $50-$150

Rare But Worth Checking

• Fractured Transmission Shift Cable (4-Speed Models): → Shop Transmission Assembly A recall (NHTSA #14V224000, GM #09041) was issued for Auras with the 4-speed automatic transmission. The cable could fracture, causing a mismatch between the gear selector position and the actual transmission gear, preventing it from going into Park and creating a rollaway hazard. This can set fault codes.
• Wiring Harness Damage: Damage to the wiring between the ECM and TCM can cause communication errors (like U0101) and trigger a P0700. Inspect the harness for any signs of chafing, corrosion, or damage, especially where it passes near hot or moving components like the cylinder head.

Diagnosis Steps

1. Connect an advanced scan tool capable of reading manufacturer-specific codes from the Transmission Control Module (TCM). Do not rely on a basic code reader.
2. Record all codes stored in the TCM. The P0700 is just the messenger; the other codes (e.g., P0776, U0101) will point to the actual problem area.
3. Check the transmission fluid level and condition. Look for a burnt smell or metallic debris, which strongly suggests internal mechanical failure (like the wave plate).
4. If communication codes like U0101 are present, test the power and ground circuits at the TEHCM connector. A stable power supply and good ground are essential for the module to function. If power and ground are good, the TEHCM has likely failed.
5. Follow the specific diagnostic procedures for any other codes found. For example, a P0776 code combined with a loss of 3rd, 5th, and Reverse is a near-certain indicator of a broken 3-5-R wave plate.
6. Check for eligibility under GM's Special Coverage Adjustment 14404B by providing a dealer with your VIN if a wave plate failure is suspected.
7. Final confirmation of a broken wave plate requires removing the transmission's side cover and clutch housing for visual inspection.

Parts You'll Likely Need

• Transmission Control Module (TEHCM) (OEM #24256861) — A common failure point on this platform, the TEHCM is located inside the transmission and is often the root cause when communication or multiple solenoid codes are present. Replacement requires programming.
  Trusted brands: ACDelco (OEM), Dorman
  OEM price range: $400-$600
  Aftermarket price range: $250-$450
• 3-5-R Clutch Wave Plate (OEM #24254103) — This specific part is the updated version designed to fix the common fracture issue in the 6-speed 6T70/6T75 transmission. It's essential for any rebuild involving these symptoms.
  Trusted brands: ACDelco (OEM)
  OEM price range: $15-$30
  Aftermarket price range: $10-$20
• Transmission Overhaul/Rebuild Kit (OEM #24269587 (for 2007-2008 models)) — Required for a wave plate repair. Includes all necessary seals, gaskets, and O-rings to properly reassemble the transmission after it has been opened for the wave plate replacement.
  Trusted brands: ACDelco (OEM), Transtar, Precision International
  OEM price range: $200-$350
  Aftermarket price range: $150-$250

Related Codes That Often Appear With This One

• P0776 / P0777 — These codes for Clutch Pressure Control (PC) Solenoid 2 (Stuck Off/On) are the most common companions to a 3-5-R wave plate failure in 6-speed transmissions. The broken plate prevents the clutch from applying correctly, which the TCM interprets as a solenoid/pressure fault.
• U0101 — This code means 'Lost Communication with TCM' and points directly to a failed TEHCM, a bad wiring connection to the TEHCM, or a power/ground supply issue to the module.
• Any P075x-P079x code — This range of codes points to specific shift solenoid or pressure switch circuit faults. On the 6T70, since the solenoids are part of the TEHCM, these codes almost always necessitate a TEHCM replacement.

Technical Service Bulletins (TSBs) & Recalls

• GM TSB 14404B: Special Coverage Adjustment for broken 3-5-R wave plates in 6T70/6T75 transmissions. This extended the warranty to 10 years or 120,000 miles for this specific failure. It details the condition (loss of 3rd, 5th, and Reverse gears) and lists all affected vehicles, including the Saturn Aura. The TSB instructs technicians to replace the wave plate and thoroughly clean the transmission of debris.
• GM TSB 08-07-30-022E: This technical service bulletin (referenced in other TSBs) provides information on the updated 3-5-R wave plate (part number 24254103) designed to prevent the fracture issue. It recommends installing the new plate anytime the transmission is disassembled.
• NHTSA Recall 14V152000 (GM #14152): Addresses a fractured transmission shift cable on 2007-2008 Saturn Auras equipped with the 4-speed automatic transmission. The cable can break, preventing the driver from selecting Park and potentially leading to a rollaway risk. The remedy was to replace the shift cable assembly and mounting bracket.

Platform-Specific Known Issues

• Special Coverage 14404B was issued by GM for the broken 3-5-R wave plate in the 6-speed automatic transmission, extending the warranty to 10 years or 120,000 miles for this specific repair.
• Safety Recall 14V152000 (GM #12106) was issued for fractured transmission shift cable ends on 4-speed models, which could cause the vehicle to roll away.

Mechanic-Grade Diagnostic Values

• 6T70 Shift Solenoid Resistance — expected: 20-40 ohms. Failure: A reading outside this range indicates a faulty solenoid coil.
• 6T70 PWM VBS Solenoid Resistance — expected: 4-7 ohms. Failure: A reading outside this range points to a problem with the pressure control solenoid.
• 4T45-E Shift Solenoid (A or B) Resistance — expected: 19-31 ohms. Failure: Resistance outside this range suggests the solenoid needs replacement.
• CAN Bus Network Resistance (at DLC, TCM disconnected) — expected: ~120 ohms. Failure: A reading significantly different from 120 ohms suggests a problem with the wiring or the other terminating resistor on the network (often in the BCM).
• CAN Bus Network Resistance (at DLC, all modules connected) — expected: ~60 ohms. Failure: A reading other than ~60 ohms indicates a network wiring issue or a module pulling the bus down.

Scan Tool Commands That Help

• GDS2 / Tech2: SPS (Service Programming System) — This function is required to program a new TEHCM to the vehicle. The new module will not function until it is programmed with the correct VIN and software calibration.
• GDS2 / Tech2: Solenoid Cleaning Procedure — If a solenoid performance code is present but a hard electrical fault is not, a technician may command a solenoid cleaning cycle. This rapidly pulses the solenoid in an attempt to dislodge small pieces of debris. If the code returns, TEHCM replacement is likely necessary.
• GDS2 / Tech2: Transmission Fluid Life Monitor Reset — After performing a transmission fluid and filter change, this function must be used to reset the fluid life percentage back to 100%.

Wiring & Ground Locations

• G107 — On the right front of the engine.. This is a primary ground point for the engine and transmission control modules on some configurations. A corroded or loose connection at G107 can cause a wide range of intermittent issues, including communication codes like U0101, which triggers P0700.
• TEHCM Main Connector — On the side of the transmission case, where the main vehicle harness connects to the internal TEHCM.. This 20-pin connector is the single point for all power, ground, and data communication to the TEHCM. Verifying power and ground at the correct pins here is the first step before condemning the internal TEHCM.
• Underhood Fuse Block — In the engine compartment, typically near the battery.. The TEHCM receives power via dedicated fuses in this block (e.g., TCM/TRANS fuse). A blown fuse will cause a complete loss of communication (U0101) and set a P0700.

Real Owner Repair Stories

• YouTube channel 'Broken Cars with Johnnie Mic' (2008 Saturn Aura) — Intermittent problem with speed sensor code, speedometer would get stuck at 20 mph, and the vehicle required heavy throttle to accelerate.
  ❌ Tried (didn't work) Replacing the speed sensor.
  ✅ What actually fixed it The final fix involved repairing multiple wiring issues. A main ground on the transmission was corroded and cleaned. More importantly, a section of the wiring harness was found to be rubbing against the cylinder head, exposing bare wire and causing an intermittent short to ground. Repairing the damaged wires and securing the harness away from the engine resolved the intermittent electronic faults.
• YouTube channel 'BL Automotive' (2008 Saturn Aura) — No crank, no start condition with multiple communication codes across various modules (ECM, TCM).
  ❌ Tried (didn't work) Initial diagnosis pointed towards a bad ECM or TCM.
  ✅ What actually fixed it The root cause was a poor connection at the Body Control Module (BCM), which acts as the central gateway. Wiggling connector X2 on the BCM would cause the communication network to come back online, allowing the car to start. The connector had evidence of prior work (dielectric grease) and a loose pin connection was the ultimate fault, not the TCM or ECM.
• NHTSA ODI #10566075 — An owner reported paying $650 to have four new speed sensors/solenoids and variable timing actuators installed to address a series of codes including P0700, but the vehicle continued to experience issues.

OEM Part Supersession History

• 24223806 → 24254103 — The original 3-5-R wave plate was prone to fracturing due to a design flaw. The updated part (24254103) is made from stronger, shot-peened material to resist cracking.
  Heads up: Aftermarket company Sonnax offers a 'drum saver' kit 124555K which includes a toothless wave plate design to prevent it from catching on splines if the drum is slightly damaged.
• Varies by year → 24256861 (Common service replacement) — Part numbers for the TEHCM have been updated over time to reflect hardware and software revisions. 24256861 is a widely used replacement part for this era of 6T70 transmissions.
  Heads up: A new TEHCM must be programmed to the vehicle's VIN using GM's Service Programming System (SPS) before it will function. A used TEHCM from another vehicle generally cannot be reprogrammed and should not be used.

Model Year Variations Within This Range

• 2007-2008 vs 2009: GM issued different transmission service seal kits for the wave plate repair: P/N 24269587 for 2007-2008 models and P/N 24269586 for 2009 models, indicating minor internal differences in seals and gaskets between the years.
• 2007-2009: The 6-speed 6T70 transmission was used with the 3.6L V6 engine, while the 4-speed 4T45-E was used with the 2.4L I4 and 3.5L V6 engines. The causes, symptoms, and repairs are vastly different. The 4T45-E has serviceable individual shift solenoids, while the 6T70 has them integrated into the non-serviceable TEHCM.

Diagnostic Flowchart

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: A complete, used transmission assembly from a low-mileage donor vehicle can be a cost-effective alternative to a full rebuild, especially if the failure is major internal damage beyond just the wave plate. However, this is a gamble on the condition of the used unit's TEHCM and clutches.

Donor-vehicle mileage cap: roughly under 80000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• Verify the donor vehicle's VIN to confirm the year and model to ensure compatibility.
• Check the color and smell of the transmission fluid from the donor unit if possible. Bright red fluid without a burnt smell is a good sign.
• Inspect the main electrical connector for any signs of corrosion, damage, or bent pins.
• Ask for any available service history on the donor vehicle.
• Ensure the torque converter is included and properly secured for transport to prevent damage to the pump seal.

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

• Transmission Electro-Hydraulic Control Module (TEHCM): A new OEM or OEM-quality remanufactured unit is strongly recommended. Used TEHCMs are typically locked to the original vehicle's VIN and cannot be reprogrammed, making them unusable.

Aftermarket brands forum-validated for this vehicle:

• Sonnax: For internal rebuild components like their 3-5-R drum saver kit (124555K), which is considered an upgrade over the OEM wave plate design by many professional rebuilders.

Brands owners have reported issues with on this vehicle:

• No-name, unverified online sellers of pre-programmed TEHCMs. Programming is critical and must be done with legitimate, up-to-date software linked to the vehicle's VIN. A faulty program can cause shifting issues or render the vehicle inoperable.

Real Owner Stories

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

Related OBD-II Codes

• P0776 — This code for 'Clutch Pressure Control Solenoid 2 Stuck Off' is a primary indicator of the common broken 3-5-R wave plate failure in the 6T70 transmission, which triggers the P0700.
• U0101 — Indicates 'Lost Communication with TCM'. When this code is present, the P0700 is set because the Engine Control Module (ECM) cannot get status from the transmission, often due to a failed TEHCM or a wiring issue.
• P0751 — A specific shift solenoid performance code. On the 6-speed Aura, the solenoids are part of the TEHCM assembly. This code points to an internal TEHCM failure, which in turn causes the P0700 to be stored.
• P0752 — Another solenoid-specific code ('Shift Solenoid A Stuck On'). Like other P075x codes on this vehicle, it typically indicates a fault within the non-serviceable TEHCM, requiring a full module replacement to resolve the root cause of the P0700.

Frequently Asked Questions