12 is normal and always displays three times, then the other stored codes display, good job reading it! Here's the scoop.
26. Quad-driver module fault, or no throttle switch input 27. Quad driver module #2 circuit fault, or open throttle switch.
44. Oxygen Sensor reads lean (low voltage of 0.2 or less), or left O2 sensor reading lean.
CODE 26, QUAD-DRIVER CKT, (1 OF 3) Each ECM Quad-Driver has a fault line which is monitored by ECM. ECM compares voltage values of fault line with acceptable values in ECM memory. If ECM senses values other than accepted values, a Code 26 will set. QDM "B" will not set a Code 26. 1. ECM does not know which controlled circuit set Code 26. This tests SERVICE ENGINE SOON light driver and circuit. 2. QDM symptoms: Ã TCC inoperative (Code 39). Ã Hot light/check gauges light always on, off during bulb check Ã Cooling fan always on or will not come on at all. Ã Poor driveability due to 100 percent canister purge. DIAGNOSTIC AIDS Coolant temperature sensor, in rare cases, may fail to indicate correct coolant temperature without setting a malfunction code (Code 14 or 15). This could result in turning on hot light without having an overheating condition. It could also result in engine overheating without turning on hot light. Check coolant sensor. See COOLANT TEMPERATURE RESISTANCE TEST table in SENSOR RANGE CHARTS article in this Section. HOT LIGHT OR CHECK GAUGES LIGHT DIAGNOSIS Hot light/check gauges light is powered by 10-amp GAGES fuse. Light will turn on when ECM provides a ground for circuit. If circuit grounds between light and ECM, light will glow anytime ignition is turned on. 1. Turn ignition on with engine off (bulb test). If hot light/check gauges light glows, go to step 3). If hot light/check gauges light does not glow, check following: Ã 10-amp GAGES fuse. Ã Faulty instrument cluster bulb. Ã Open circuit between fuse and hot light/check gauges light. 2. Backprobe terminal YF2 at ECM using a test light to battery voltage. Turn ignition on. If test light does not glow, ECM terminal connection is bad or ECM is faulty. If test light glows, turn ignition off. Disconnect ECM connectors. Jumper terminal YF2 to ground. Turn ignition on. If hot light/check gauges light does not glow, check for open circuit between light and ECM. If NOTE: Test numbers refer to numbers on diagnostic chart. NOTE: Models equipped with an indicator cluster have a hot temperature light on dash. Models equipped with a gauge cluster have a check gauges light. These checks assume vehicle is not overheating. Verify proper operation of cooling system before diagnosing hot light/check gauges light. Light does not glow, all circuits (including bulb) are intact and power is available to light, instrument cluster must be replaced. 3. Start engine. If light goes off, no problem is evident. See DIAGNOSTIC AIDS. If light is on, turn ignition off. Disconnect ECM connector. Probe ECM harness terminal YF2 using a test light to battery voltage. If light is off, replace ECM. If light is on, repair short to ground in circuit No. 35. If no short is present, replace instrument cluster.
CODE 26, QUAD-DRIVER CKT, W/3T40 TRANS. (2 OF 3) On models with 3T40 transmission, QDM "A" fault status on "Scan" tester should read HIGH until 2nd gear switch is closed or brake is applied. To simulate driving in 2nd gear and change status to LOW, disconnect TCC connector, and connect test light between harness terminals "A" and "D". 3) This step determines which circuit is out of specification. DIAGNOSTIC AIDS Monitor voltage of each terminal while moving related harness connectors, including ECM harness. If fault is induced, voltage will change. This may help locate intermittent problems. If code reappears with no apparent problems, replace ECM. NOTE: Test number refers to number on diagnostic chart.
CODE 26, QUAD-DRIVER CKT, (3 OF 3) 4) This step determines if problem is circuit or component. Factory-installed ECM has an internal fuse and is unlikely to need replacement. Fig. 31: Code 26, Quad-Driver Ckt (3 of 3) Fig. 32: Code 26 Flow Chart (Part 3 of 3) CODE 27 OR 28, GEAR SWITCH CKTS, W/3T40 TRANSAXLE Gear switches are located inside transaxle. Switches are normally closed. As vehicle speed increases, hydraulic pressure applies specific gear clutches and gear switch opens. ECM uses gear switches input signals in calculations to determine control fuel delivery and TCC operation. Code 27 will set if mid gear 2nd switch indicates ground or closed switch for 12 seconds when vehicle is in 3rd gear or if mid gear 2nd switch circuit indicates an open when engine is first started. Code 28 will set if high gear 3rd switch circuit indicates ground or closed switch for 10 seconds when vehicle is in 3rd gear or if high gear 3rd circuit indicates an open when engine is first started. 1. A digital volt-ohmmeter must be used in this test. A test light will not work due to low voltage supplied by ECM. 2. Checks if circuit is grounded through switch. 3. Checks for a good, properly operating switch and checks circuit within transaxle for an improper ground. DIAGNOSTIC AIDS Check for poor connections at ECM pins. Inspect harness for incorrect routing (too close to high voltage wiring) and chafing. Monitor voltage of each terminal while moving related harness connectors. If failure is induced, voltage reading will change. NOTE: Test number refers to number on diagnostic chart. NOTE: Test numbers refer to numbers on diagnostic chart.
This all can be either a bad 02 sensor, causing the engie to remain in open loop(cold engine) operation or a bad ECT(engine coolant temp sensor), Some were called CTS Coolant temp sensor. This also would cause cold engine operation all the time. It acts like a choke for fuel injected cars. Check your email I will send full testing info.
Thursday, April 15th, 2010 AT 1:24 PM