WHT Z06: Fixes

Fix	Description
Brake Pedal Sensor	Brake Pedal Position Sensor Replacement
CAGS Solenoid	CAGS Solenoid Replacement
Clutch Pedal Spring	Clutch Pedal Return Spring Replacement
Exhaust Solenoid	Dual Mode Exhaust Solenoid Valve Replacement
Floor Mats	Floor Mats Upgrade
Fob	Fob Panic Button Disable
Lug Nuts	Lug Nuts Upgrade
Parking Brake Cables	Parking Brake Cable Replacement
Quarter Panel Debris	Quarter Panel/Rocker Panel Debris TSB
Reverse Solenoid	Reverse Lockout Solenoid Replacement
Steering Wheel Sensor	Steering Wheel Position Sensor Replacement
Steering Wheel Squeak	Steering Wheel Squeak Fix
Sway Bar Click	Sway Bar End Links Click Fix
Turn Signal	Turn Signal/High Beams Fix
US Flag	Aluminum US Flag
Weatherstrip Lubricant	GM Weatherstrip Lubricant
Wheel Bearing	Wheel Bearing Replacement
XM Band Deletion	Remove the XM band From The Radio

Brake Pedal Position Sensor Replacement

At around 90K miles I started getting the dreaded "SERVICE ACTIVE HANDLING" along with the the active handling code C0161, symptom 11. I was frequently unable to engage the cruise control or it would drop out for no apparent reason. The factory service manual says the conditions for setting this code/symptom are:

• The brake pedal is sensed as applied.
• The vehicle speed is greater than 40 km/h (25 mph).
• The vehicles acceleration exceeds 8 km/h per second (5 mph per second).

First I tried calibrating the sensor with a Tech2. This teaches the Electronic Brake Control Module (EBCM) where the "foot off" brake pedal position is. When that didn't improve the situation I tried replacing the brake pedal position sensor which was cheap enough.

GM	Description
13579090	Brake Pedal Position Sensor (1st design)
10302722	Brake Pedal Position Sensor (my old one)
13597429	Brake Pedal Position Sensor (revised)

Pro-tip from the Corvette Forum: Remove the sensor and bracket as a unit, disconnect the harness, and swap the sensor on the bench; replacing the sensor while still in the car and attached to the bracket is very difficult.

Brake Pedal Position Sensor

Fun trivia: The brake pedal sensor part number (13597429) is also used as the clutch pedal sensor on the 2nd gen CTS-V Cadillac (2009-2014).

Even after calibrating the new sensor the car kept throwing the code. At this point I eventually figured out that when the cruise control would not engage the brake lights were on! This made a lot of sense and made me want to inspect/clean any connectors between the sensor and the EBCM. However the EBCM is a borg-like assembly of electronics and valves located in the engine compartment and adult hands are too large to get at the connector. Fortunately I spent some time studying the factory wiring diagrams and figured out that the brake pedal sensor connects to the body control module (BCM) which is behind the passenger kick panel and readily accessible. So I disconnected the battery, removed J2, applied dielectric grease to the connector terminals, and reinstalled.

BCM Connector J2

I re-calibrated the sensor one final time and that was the end of the problem. Knowing what I know now, next time I would start with the connector …

CAGS Solenoid Replacement

My T56 transmission has leaked a tiny amount of ATF over the past few years. Googling showed one possible source is the skip shift (aka CAGS) solenoid. Apparently the original design starts to leak internally. One way to solve this is to replace the solenoid with a plug (e.g. the one sold by ICT Billet) but if you do that you'll need to plug an aftermarket skip shift eliminator into the harness or else you'll get an engine check light. But since I use the CAGS LED Fuse method I need the solenoid to be connected and present.

Original and Replacement

When I removed the old solenoid I found ATF in the connector. Given it has a seal between it and the the transmission case it was pretty obvious that the leak was internal to the solenoid.

Just like the reverse lockout solenoid, the original takes a 34mm deep socket and the replacement a 27mm.

Clutch Pedal Return Spring Replacement

After about four years of fun my clutch pedal return spring broke. This was apparently a common problem. Some switched to the C5 Corvette version which is supposed to be softer.

GM	Description
12555205	Clutch Pedal Return Spring (C5)
10376347	Clutch Pedal Return Spring

Others liked not having a spring at all. I replaced mine with the original part which has held longer than the original; I suspect there were quality control issues.

Original	Replacement	Installed

Dual Mode Exhaust Solenoid Valve Replacement

When my Z06 reached about 17 years I noticed that the dual mode exhaust would sometimes get stuck in "loud" mode. It got to the point where once the car was warmed up the computer was unable to close the butterflies. These are normally open and engine vacuum is used to close them. The system to control them consists of a class2/J1850 network module, a solenoid valve, a spherical vacuum reservoir, and a vacuum controlled butterfly at each exhaust tip. The ECM commands the butterflies to open for these conditions:

• Throttle position is 25% or greater
• Engine RPM 3500 or greater (3000 when in competition mode)

As with other solenoid failures, the intermittent nature of the the failure made me suspect the solenoid valve.

GM	Description
25794609	Exhaust Vacuum Control Solenoid Valve (w/tubing)
22902593	Exhaust Vacuum Control Solenoid Valve
25794610	Exhaust Vacuum Control Solenoid Valve

Neither the old nor the new part had GM part numbers on them but the new one came in GM packaging. Both were made by Pierburg:

Part Number	Description
7.00953.00	Original
7.00953.01	Replacement

The new Pierburg part number likely corresponds to the change in GM part numbers.

New Solenoid Valve	Installed

The vacuum lines were really stuck on the old part and it took a bit of force to remove them; I used some dielectric grease when I installed the new part.

Floor Mats Upgrade

Service bulletin 08-08-110-010 describes the conversion and the text is available here. Here is the list of parts I used:

GM	Description
25864433	Floor Mats, Carpet, Front (ebony)
10351595	Hook, Front Floor Panel Carpet

My strategy was to use masking tape and a sharpie to mark the position of the old mats and then cut slits in the carpet for each hook such that the new mats would end up in the same place.

Notes:

• You need two hooks for the left/driver's side and one for the right/passenger.

• The location of the right/passenger side hook moved in late 2013.

• When installed the hooks cover the old stud holes in the carpet.

Fob Panic Button Disable

Lug Nut Upgrade

I've yet to meet anyone who like the sheet metal wrapped OEM lug nuts. They are universally hated. It's just a matter of time until your tire technician spins the sheet metal with an impact gun.

When mine started to get in bad shape I picked up a set of Chinese lug nuts from ebay. It's difficult to beat the price but the chrome plating was less than stellar and after a year or two they started rusting.

Eventually I bit the bullet and got a set of McGard 64012 Lug nuts. these are M12 X 1.5. They have a lifetime warranty to not chip, peel, or rust.

Lug Nuts: OEM, cheap-o, McGard

Parking Brake Cable Replacement

I popped a parking brake cable when my Z06 was about ten years old. I guess that's what I get for always using it.

I decided to replace both cable and given that I found it necessary to remove the exhaust intermediate pipes this was probably the right move.

Quarter Panel/Rocker Panel Debris TSB

During the first few years I frequently found small rocks and dirt trapped between the rocker panels and the quarter panels. Eventually I found TSB 11-08-65-001A, which is titled, "Information on Small Rocks, Sand and Gravel (Road Debris) Trapped Between Quarter Panel and Rocker Panel and Installing Adhesive Back Shim Stock."

1 of 4	2 of 4	3 of 4	4 of 4

I was able to obtain a lifetime supply of the foam tape ("shim stock") from Kent Automotive, it was not difficult to install, and it definitely solves the issue. Although it would not surprise me if it just means that debris is still building up behind the rocker panels …

Part Number	Description
P46515	Kent Automotive Shim Stock (9/16" thick, 1" wide)
P46500	Kent Automotive Shim Stock (5/16" thick, 3/4" wide)

Given that this only applies to 2005-2011 Corvettes I suspect Chevrolet started applying foam tape at the factory in late 2011.

Reverse Lockout Solenoid Replacement

I started noticing that sometimes reverse was available while driving down the road. This was because my reverse lockout solenoid was failing. I replaced it with the car jack stands. It was not an easy process.

Original	Replacement

The original solenoid was much larger than the replacement (GM 19178634). The factory service manual calls for a Kent Moore J-41099 (which is a fairly deep 34mm socket) which I didn't have at the time but honestly I'm not convinced there is a enough room to use a ratchet with the transmission still in the car so ultimately I found it easier to remove the entire assembly and replace the solenoid on the bench using a large crescent wrench. I was able to torque the new solenoid in with a 27mm deep socket.

After removal I tested the original solenoid with a suitable 12V power supply; I found that it frequently would stick in the retracted position, which accounted for the symptoms I observed.

Steering Wheel Position Sensor Replacement

For a number of years, my Z06 would throw the active handling code C710, symptom 1F. The factory service manual says the conditions for setting this code/symptom are:

• The ignition is ON.
• Ignition voltage is greater than 8 volts.
• The steering wheel position sensor has been powered ON for 0.2 seconds.
• The steering rate of Phase A is less than 80 degrees per second.

In addition symptom 1F is flagged as "intermittent" which was certainly my experience. The code would most often appear at low speed while moving the steering wheel back and forth a lot, for example when maneuvering in a parking lot.

The first TSB to address this is 06-02-35-002, dated January 2006. It basically says the motion of the telescoping/tilt steering wheel may cause a high resistance condition in the steering wheel position (SWPS) connector. The described remedy is to wrap connector C202 (located on the steering column) in electrical tape and install a zip-tie around the tape. It also says it's important to remove/install the SWPS connector "a minimum of three times to remove any possible terminal corrosion."

My 2007 Z06 already had the tape and zip-tie and so I applied some dielectric grease and reseated the SWPS "a minimum of three times" but it was only a short term solution.

The original TSB was revised in October of 2007 by 06-02-35-002B. It involves installing a new terminal positive assurance (TPA) clip.

GM	Description
19179794	Steering Angle Sensor Lead Clip

A TPA is a device that prevents terminals from accidentally coming out of a connector. And it's interesting to note that C202 already had a TPA in place; I believe the new part is a secondary TPA designed to prevent any movement of the terminals in the connector. It also prevents C202 from being disengaged from the SWPS itself.

The next time the car threw the code I decided to bite the bullet and replace the SWPS. This requires removing the steering column from the vehicle which wasn't as difficult as I was expecting.

Steering Column

The new sensor was not expensive (~$100) but the factory service manual is unnecessarily intimidating. It references the J-42640 "steering column anti-rot pin" which is a metal rod that is inserted into the steering column to limit rotation of the steering shaft and prevent uncentering and damaging of the SIR coil.

J-42640

Some have reported not using the tool but to be safe I ordered one. It's 0.2340" in diameter (the same size as an "A" twist drill bit) and honestly a phillips screwdriver of that size or slightly smaller would probably do the job just as well. In the end the tool limits the steering wheel to about +/- 1/8 of a turn from center.

The new SWPS comes with a pin installed that keeps it aligned. I found I could see inside the hole on the old sensor well enough to know when it was positioned exactly straight ahead. It was a simple matter to swap the sensors and pull the pin out of the new one.

GM	Description
15231656	Steering Wheel Position Sensor (w/telescopic)

The new SWPS appears to have solved my issue. Inspection of the old sensor revealed a small buildup of black powdery residue; I suspect it was just worn out.

Old Steering Wheel Position Sensor	New Steering Wheel Position Sensor

Steering Wheel Squeak Fix

Recently my steering wheel started to squeak. The solution was to remove the steering wheel and spray a little silicone into the small gap between the plastic rotating parts.

Steering Wheel SIR Coil

Sway Bar End Links Click Fix

When my Z06 was about five years old I started noticing a clicking sound coming from the suspension when driving over driveways. This was reported on the Corvette Forum to be do to the sway bar end links.

Sway Bar End Link

I bought and installed replacements which fixed the noise.

GM	Description
20822934	Suspension Stabilizer Shaft Link

Eventually TSB PIC4475B was issued, "Snap Clunk Noise From Front Or Rear Of Vehicle - keywords click link noise snap stabilizer stable suspension." It suggests replacing any end links that make noise.

Turn Signal/High Beams Fix

Around 90K miles I noticed that sometimes my high beams would come on when making right turns. This turned out to be a well documented problem with the turn signal (aka multifunction switch).

Multifunction Switch	Multifunction Switch Installed

Removing and reinstalling the steering column trim is the most difficult part of the job.

GM	Delco	Description
20808029	D6244E	Turn Signal, Headlight, Headlamp Dimmer, etc. Switch

Aluminum US Flag

GM Weatherstrip Lubricant

It's listed in TSB (#99-08-64-016A) as being one of the two products that should be periodically applied to weatherstrip surfaces. A cheaper option is dielectric silicone grease (GM 12345579 or equivalent).

Wheel Bearing Replacement

After about ten years of fun I started noticing an obvious wheel bearing noise coming from the rear. My best guess was that it was the left rear. using a Steelman "Chassis Ear" box I was able to definitely identify wheel (it was opposite from my guess).

Wheel Bearing

As recommended I replaced the axle shaft nut, applied Loctite 272 and torqued to 160 lb/ft.

GM	Delco	Description
88967288	RW20-86	Rear wheel hub
10257766		Rear axle shaft nut

Remove the XM band From The Radio

When the radio does not receive any frames on the J1850 bus from the XM module it not display a soft button for XM bands.

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Craig Leres