Need to disconnect ground cable on battery - 2000 Toyota ECHO

Technically, no as long as there isn't any power going to the headlamps there is not need to disconnect the battery cable. BUT any operator's manual will tell you ALWAYS disconnect the positive cable from the battery (or disconnect power source) when doing any sort of work on anything that has power, because you never know. If you remove the negative - you risk still grounding to the chassis if you place the cable loosely inside the engine compartment.

If you need further help, reach me via phone at https://www.6ya.com/expert/michael_e7c2c48c6e65f808

Technically, no as long as there isn't any power going to the headlamps there is not need to disconnect the battery cable. BUT any operator's manual will tell you ALWAYS disconnect the positive cable from the battery (or disconnect power source) when doing any sort of work on anything that has power, because you never know. If you remove the negative - you risk still grounding to the chassis if you place the cable loosely inside the engine compartment.

If you need further help, reach me via phone at https://www.6ya.com/expert/michael_e7c2c48c6e65f808

Here are some steps that you need to do.

• Disconnect battery ground cable at battery.
• Remove drive belt.
• Disconnect alternator electrical connector.
• Disconnect battery positive cable nut on alternator.
• Remove alternator
• Put the new alternator
• Connect the positive cable nut and electrical connector
• Connect the battery ground cable
• Start the car then check if its giving enough charge to your battery

Crankshaft Position Sensor Removal & Installation 5.4L & 6.8L Engines To Remove:
Before servicing the vehicle, refer to the precautions in the beginning of this section.

1. Remove or disconnect the following:
   • Battery ground cable
   • Accessory drive belt
   • A/C compressor electrical connector
   • Position A/C compressor aside
   • Crankshaft position sensor electrical connector
   • Bolt and the sensor

To Install:

1. Install or connect the following:
   • CKP sensor torque bolt to 89 in. lbs. (10 Nm)
   • Crankshaft position sensor electrical connector
   • A/C compressor and electrical connector
   • Accessory drive belt
   • Battery ground cable

6.0L Engine To Remove:
Before servicing the vehicle, refer to the precautions in the beginning of this section.

1. Remove or disconnect the following:
   • Battery ground cables.
   • Crankshaft position sensor electrical connector.
   • Bolt and the sensor

To Install:

1. Install or connect the following:
   • CKP sensor torque bolt to 8 ft. lbs. (11 Nm).
   • Crankshaft position sensor electrical connector.
   • Battery ground cable

Heated Oxygen Sensor (HO2S)- The Bank 1 Sensor 1 tells me that it's an upstream O2 sensor. The larger the number the further down the line of the exhaust it is. Removal & Installation 4.2L Engine
To Remove:

1. Raise and safely support vehicle.
2. Disconnect battery ground cable.
3. Detach electrical connector from right inner fender splash shield (if necessary).
4. Remove right inner fender splash shield (if necessary).
5. Disconnect heated oxygen sensor electrical connector.
6. Remove heated oxygen sensor.

To Install:

1. Apply anti-seize lubricant to heated oxygen sensor threads.
2. Install heated oxygen sensor. Torque to: 34 ft-lbs (46 Nm)
3. Connect heated oxygen sensor electrical connector.
4. Install right inner fender splash shield (if necessary).
5. Attach electrical connector to right inner fender splash shield (if necessary).
6. Connect battery ground cable.
7. Lower vehicle.

4.6L and 5.4L Engines
To Remove:

1. Raise and safely support vehicle.
2. Disconnect battery ground cable.
3. Disconnect heated oxygen sensor electrical connector.
4. Remove heated oxygen sensor.

To Install:

1. Apply anti-seize lubricant to heated oxygen sensor threads.
2. Install heated oxygen sensor. Torque to: 34 ft-lbs (46 Nm)
3. Connect heated oxygen sensor electrical connector.
4. Connect battery ground cable.
5. Lower vehicle.

2.0L DOHC Engine
See Figure 4

1. Disconnect the negative battery cable.
2. Disconnect the starter motor electrical connections.
3. Remove the starter motor mounting bolts and remove the starter.

Fig. Fig. 4: Exploded view of the starter motor mounting-2.0L engine
To install:

1. Clean both surfaces of the starter motor flange and the rear plate. This is important since the starter grounds through its case and the transaxle flange to which it attached. Some remanufactured starters may have paint on these areas which should be cleaned off before installation. Install the starter motor onto the transaxle and secure with the retaining bolts. Tighten the bolts to 40 ft. lbs. (54 Nm).
2. Attach the electrical harness connectors to the starter.
3. Connect the negative battery cable and check the starter for proper operation.

2.0L SOHC Engine With Manual Transaxle
See Figures 4 and 5

1. Disconnect the negative battery cable from the left strut tower. The ground cable is equipped with a insulator grommet which should be placed on the stud to prevent the negative battery cable from accidentally grounding.
2. Remove the air cleaner resonator.
3. Remove the positive battery cable retaining nut from the starter.
4. Disconnect the positive battery cable and alternator output wire from the starter.
5. Disconnect the push-on solenoid connector from the starter.
6. Remove the 2 bolts that attach the starter to the transaxle.
7. Remove the starter from the vehicle.

Fig. Fig. 5: Starter motor wiring terminal connections-2.0L engine To install:

1. Install the starter and the attaching bolts to the transaxle assembly.
2. Tighten the attaching bolts to 40 ft. lbs. (54 Nm).

Clean all dirt and/or corrosion from the wire terminals before reconnecting the wiring to the solenoid.

1. Reconnect the push-on solenoid connector to the starter.
2. Reconnect the alternator output wire and positive battery cable to the starter and tighten the retaining nut to 90 inch lbs. (10 Nm).
3. Install the air cleaner resonator.
4. Reconnect the negative battery cable.

2.0L SOHC Engine With Automatic Transaxle; 2.4L Engine
See Figures 4, 5 and 6

1. Disconnect the negative battery cable from the left strut tower. The ground cable is equipped with a insulator grommet which should be placed on the stud to prevent the negative battery cable from accidentally grounding.
2. Remove the air cleaner resonator.
3. Remove the 3 bolts attaching the Transmission Control Module (TCM). Do not disconnect the TCM wiring. Move the TCM to gain access to the upper starter mounting bolt.
4. Remove the upper starter mounting bolt.
5. Raise and safely support the vehicle.
6. Remove the positive battery cable nut and disconnect the cable from the starter.
7. Disconnect the push-on solenoid connector.
8. Remove the lower mounting bolt that attaches the starter to the transaxle.
9. Remove the starter from the vehicle.

Fig. Fig. 6: Starter motor wiring terminal connections-2.0L SOHC engine with A/T; 2.4L engine To install:

1. Install the starter onto the transaxle and the lower mounting bolt.
2. Tighten the mounting bolts to 40 ft. lbs. (54 Nm).

Before reconnecting the wiring to the starter solenoid, be sure to clean the wiring of any dirt or corrosion.

1. Reconnect the positive battery cable to the solenoid post and tighten the retaining nut to 90 inch lbs. (10 Nm).
2. Reconnect the push-on solenoid connector.
3. Lower the vehicle.
4. Reinstall the upper attaching bolt and torque to 40 ft. lbs. (54 Nm).
5. Reinstall the TCM to its original location and install the mounting screws.
6. Reinstall the air cleaner resonator.
7. Reconnect the negative battery cable

Hope helped.

To Remove:

1. Disconnect the battery ground cable.
2. Remove the speedometer cable and the shift cable.
3. Disconnect the starter motor connector and terminal.
4. Remove the starter motor assembly.

To Install:

1. Install the starter motor assembly.
2. Connect the starter motor connector and terminal.
3. Install the speedometer cable and the shift cable.
4. Connect the battery ground cable.

IF YOU UNHOOK THE NEGATIVE CLAMP FROM THE BATTERY AND YOU STILL GET A READING FROM NEGATIVE POST ON THE BATTERY TO THE FRAME YOUR METER IS COMPLETING THE 12 VOLT CIRCUIT AND THAT IS WHY YOUR READING 12 VOLTS ON YOUR METER. SOME BATTERY CABLES HAVE A SECOND GROUND FROM THE CABLE TO THE FRAME BUT IS CONNECTED AT THE BATTERY POST SUCH AS A FUSEABLE LINK WHEN YOU DISCONNECT THE CABLE YOU DISCONNECT THE GROUND. IF YOU HAD A SHORT AND READ 12 VOLTS THRU THE GROUND YOU WOULD DEFINETLY SEE SMOKE

To replace the starter you need to;
) Note if you have an anti-thief system and now to reset it if the battery is disconnected.
) Note the radio station selections if they are not saved if the battery is disconnected.

Now
) Disconnected the GROUND connector on the battery.
) Disconnect the electrical cable on the battery.
) Remove the 2 bolts holding the starter on. Remove the harder one to reach first.
) Pull the old starter out.
) Insert the new starter.
) Replace the bolt. Insert the easier bolt first.
) Tighten the bolts.
) Replace the electrical cable.
) Reconnect the GROUND connector on the battery.
) Reset any radio, clock or anti-thief systems.
) Return old starter for a core charge refund.

Sounds Like the Starter RELAY is Bad After Exhausting All other Test, Go For The RELAY
A SURE-SHOT way Is to Jumper Wire From Battery to (STARTER SIDE) of Relay if starter Works then Its the Starter Relay if NOT>>Then Its the STARTER<) Relay Instruction Below. STARTER Instructions Very Bottom
REMOVAL
WARNING: WHEN PERFORMING MAINTENANCE ON THE STARTING SYSTEM BE AWARE THAT HEAVY GAUGE LEADS ARE CONNECTED DIRECTLY TO THE BATTERY. MAKE SURE PROTECTIVE CAPS ARE IN PLACE.

1. Disconnect the battery ground cable.
   1. Disconnect the starter motor solenoid relay switch wiring.
   1. Remove the protective cover.
   2. Disconnect the push-on electrical connector.
   3. Remove the nuts.
   4. Remove the cable.
      1. Remove the starter motor solenoid relay switch.
      1. Remove the engine sensor/generator wires.
      2. Remove the bolts and ground wire.
      3. Remove the starter motor solenoid relay switch.
      INSTALLATION
      
   5. Follow the removal procedure in reverse order NOTE: When the battery is disconnected and reconnected, some abnormal drive symptoms may occur while the vehicle relearns its adaptive strategy. The vehicle may need to be driven 16 km (10 miles) or more to relearn the strategy.

REMOVAL

WARNING: WHEN PERFORMING MAINTENANCE ON THE STARTING SYSTEM BE AWARE THAT HEAVY GAUGE LEADS ARE CONNECTED DIRECTLY TO THE BATTERY. MAKE SURE PROTECTIVE CAPS ARE IN PLACE WHEN MAINTENANCE IS COMPLETED.

1. Disconnect the battery ground cable.
2. Raise and support the vehicle.
3. Remove the starter motor solenoid terminal cover.
   1. Disconnect the starter wires.
   1. Remove the nuts.
   2. Disconnect the wires.Remove the nut and the starter ground cable
   3. Remove the bolt and the starter motor.
      1. Follow the removal procedure in reverse order. NOTE: When the battery is disconnected and reconnected, some abnormal drive symptoms may occur while the vehicle relearns its adaptive strategy. The vehicle may need to be driven 16 km (10 miles) or more to relearn the strategy.